Court Opinion

ID: 4677751
Source: CourtListenerOpinion
Date Created: 2021-04-15 21:00:35.811714+00
Date Added: 2024-06-11T08:03:40.122963
License: Public Domain

In the

    United States Court of Appeals
                For the Seventh Circuit
                    ____________________
Nos. 20-1774, 20-1776, 20-1777, 20-1780, 20-1781, 20-1782, 20-
1783, 20-1784 & 20-1785
GLENN BURTON, JR., RAVON OWENS, AND CESAR SIFUENTES
                                      Plaintiﬀs-Appellees,

                                v.

E.I. DU PONT DE NEMOURS AND COMPANY, INC., THE SHERWIN-
WILLIAMS COMPANY, AND ARMSTRONG CONTAINERS, INC.
                                  Defendants-Appellants.
                    ____________________

         Appeals from the United States District Court for the
                    Eastern District of Wisconsin.
  Nos. 07-CV-0303, 07-CV-0441, 10-CV-0075 — Lynn Adelman, Judge.
                    ____________________

    ARGUED DECEMBER 9, 2020 — DECIDED APRIL 15, 2021
                ____________________

   Before WOOD, SCUDDER, and ST. EVE, Circuit Judges.
    ST. EVE, Circuit Judge. These sprawling toxic-tort cases take
us into the weeds of Wisconsin products liability law. The
product at issue is white lead carbonate—a dry white powder
historically used as the “pigment” in many lead-based paints.
Paint has two essential components: the pigment, which hides
2                                            Nos. 20-1774 et al.

and protects the painted surface, and the liquid “vehicle,”
which allows the pigment to be spread across the surface.
Over time a consensus developed that lead-based paints were
toxic and posed especially great dangers to young children,
who were prone to chewing paint ﬂakes or putting scattered
lead dust into their mouths during critical stages of brain de-
velopment. These dangers led the federal government to ban
lead-based paint for residential use in 1978. Wisconsin fol-
lowed suit two years later. Even after these bans, however,
lead-based paint remained on the walls of many homes
throughout the United States.
     The plaintiﬀs in these consolidated cases are three young
men who grew up in Milwaukee homes that had lead-based
paint on the walls. They were diagnosed with lead poisoning
as young children in the 1990s or early 2000s. Years later, they
ﬁled these lawsuits against several manufacturers of white
lead carbonate, seeking compensation for brain damage and
other injuries resulting from their ingestion of lead paint par-
ticles. The plaintiﬀs identiﬁed the paint pigment in their
childhood homes as white lead carbonate, but they could not
identify the speciﬁc company responsible for manufacturing
the white lead carbonate that they ingested. To overcome this
failure of proof, they relied on Thomas ex rel. Gramling v. Mal-
lett, 701 N.W.2d 523 (Wis. 2005), in which the Wisconsin Su-
preme Court adopted a “risk-contribution” theory of liability
for plaintiﬀs suing manufacturers of white lead carbonate.
The risk-contribution theory modiﬁes the ordinary rule in tort
law that a plaintiﬀ must prove that a speciﬁc defendant’s con-
duct caused his injury. It instead seeks to apportion liability
among the “pool of defendants” who could have caused the
injury.
Nos. 20-1774 et al.                                                      3

    After years of pretrial litigation, the plaintiﬀs went to trial
against ﬁve manufacturers of white lead carbonate. The jury
found three of the manufacturers liable and awarded the
plaintiﬀs $2 million each. The three defendants found liable
(E.I. du Pont de Nemours and Company, Inc., the Sherwin-
Williams Company, and Armstrong Containers, Inc.) now ap-
peal. They challenge a long list of the district court’s pretrial,
trial, and post-trial rulings. We see no error in many of these
rulings, and we commend the district court for its thoughtful
attention and diligent eﬀort throughout this complex case.
Nonetheless, we hold that the court committed three signiﬁ-
cant legal errors about the scope of Wisconsin products liabil-
ity law. These errors shaped the trial and impermissibly ex-
panded the defendants’ potential liability. Along with a sepa-
rate error in the admission of certain expert testimony, they
compel us to reverse the judgments and remand for further
proceedings.
                             I. Background
    Wisconsin’s risk-contribution theory is at the heart of this
appeal. 1 In this section we trace the development of the risk-
contribution theory to provide context for the plaintiﬀs’ law-
suits. We then describe the facts and procedural history giv-
ing rise to this appeal.
A. Legal Background
   1. Collins
    The risk-contribution theory has its origins in Collins v. Eli
Lilly Co., 342 N.W.2d 37 (Wis. 1984). In that case, Therese

   1   The parties agree that Wisconsin law governs these diversity cases.
4                                            Nos. 20-1774 et al.

Collins’s mother took diethylstilbestrol (DES) while pregnant
with Collins in 1957–58. DES was a miscarriage-prevention
drug that was on the market from 1947 to 1971. In 1971, med-
ical research established a possible statistical link between
DES and the later development of vaginal cancer in children
exposed to DES in utero. After developing vaginal cancer in
1977, Collins sued various drug companies that had produced
or marketed DES while her mother was pregnant.
    Under traditional tort law, Collins faced an “insurmount-
able obstacle”: she could not identify which drug company
had produced or marketed the DES that her mother had
taken. Id. at 45. She could not do so because DES was a “fun-
gible drug produced with a chemically identical formula.” Id.
at 44. Moreover, hundreds of diﬀerent companies had pro-
duced or marketed DES. And, owing to the passage of time,
records and evidence pertaining to drug companies’ produc-
tion or marketing of DES and Collins’s mother’s prescription
were largely unavailable.
    The Wisconsin Supreme Court was “faced with a choice of
either fashioning a method of recovery for the DES case which
will deviate from traditional notions of tort law, or permitting
possibly negligent defendants to escape liability to an inno-
cent, injured plaintiﬀ.” Id. at 45. While acknowledging that
“DES cases pose diﬃcult problems,” the court concluded that,
“as between the plaintiﬀ, who probably is not at fault, and the
defendants, who may have provided the product which
caused the injury, the interests of justice and fundamental
fairness demand that the latter should bear the cost of injury.”
Id. at 49. Relying on its authority under the Wisconsin Consti-
tution to fashion an adequate remedy, see Wis. Const. art. I,
§ 9, the court proceeded to adopt a risk-contribution theory of
Nos. 20-1774 et al.                                             5

recovery for DES plaintiﬀs, adding that “this method of re-
covery could apply in situations which are factually similar to
the DES cases.” Collins, 342 N.W.2d at 49. The rationale for the
risk-contribution theory was that the defendant drug compa-
nies had, at the very least, “contributed to the risk of injury to
the public” by producing or marketing a drug that turned out
to have harmful side eﬀects. Id. Moreover, the “possibly re-
sponsible” drug companies were in a better position than the
“innocent plaintiﬀ” to absorb the cost of, and protect against,
injuries from DES. Id. at 49–50.
   As for how the risk-contribution theory would apply: a
plaintiﬀ would need to sue at least one defendant and prove
“that the plaintiﬀ’s mother took DES; that DES caused the
plaintiﬀ’s subsequent injuries; that the defendant produced or
marketed the type of DES taken by the plaintiﬀ’s mother; and
that the defendant’s conduct in producing or marketing the
DES constituted a breach of a legally recognized duty to the
plaintiﬀ.” Id. at 50. While a plaintiﬀ only had to sue one de-
fendant, there were incentives to sue as many as possible, and
named defendants were free to implead other drug compa-
nies as third-party defendants.
    The court made clear that the risk-contribution theory was
available for both negligence and strict liability claims. A
plaintiﬀ proceeding on either theory would have to prove the
traditional elements of the claim, with one exception. Instead
of proving that a defendant drug company caused the plain-
tiﬀ’s injuries, the plaintiﬀ would only have to prove that the
defendant “produced or marketed the type of DES taken by
the plaintiﬀ’s mother.” Id. at 51.
   If a plaintiﬀ succeeded in making this prima facie show-
ing, the burden would shift to the defendant to prove “that it
6                                             Nos. 20-1774 et al.

did not produce or market the subject DES either during the
time period the plaintiﬀ was exposed to DES or in the relevant
geographical market area in which the plaintiﬀ’s mother ac-
quired the DES.” Id. at 52. To prevail on these defenses, a de-
fendant would have to prove that “the DES it produced or
marketed could not have reached the plaintiﬀ’s mother.” Id.
    The goal of this burden-shifting procedure was to create
“a pool of defendants which it can reasonably be assumed
could have caused the plaintiﬀ’s injuries.” Id. at 52. The court
acknowledged that the risk-contribution theory could result
in liability for innocent defendants, but it accepted this possi-
bility as “the price the defendants, and perhaps ultimately so-
ciety, must pay to provide the plaintiﬀ an adequate remedy
under the law.” Id.
    Finally, the court added that the doctrine of comparative
negligence would permit the jury to equitably “apportion lia-
bility among the defendants that have been unable to excul-
pate themselves.” Id. at 53. In allocating liability, the jury
could consider various factors, including: whether a defend-
ant tested DES for safety and eﬃcacy or took steps to protect
or warn the public; the defendant’s role in securing govern-
ment approval of DES; the defendant’s market share in the
relevant area; and whether the defendant produced or mar-
keted DES even after it knew the relevant risks. Id. at 54.
    2. Thomas
   In Thomas, the Wisconsin Supreme Court considered
whether to extend Collins’s risk-contribution theory to white
lead carbonate pigment. 701 N.W.2d at 523. Steven Thomas
suﬀered lead poisoning as a young child after he ingested
lead paint particles in two of his childhood homes. Years later,
Nos. 20-1774 et al.                                              7

Thomas sued his former landlords and several manufacturers
of white lead carbonate seeking compensation for his injuries,
which included brain damage and a heightened risk of future
medical complications.
   From a legal standpoint, Thomas was in the same boat as
Collins: he could not identify which company had manufac-
tured the white lead carbonate that he had ingested as a child,
given the “generic nature” of white lead carbonate, the large
number of producers, and the lack of available records and
evidence. Id. at 532. As such, he sought to hold the pigment
manufacturers liable under Collins’s risk-contribution theory.
The lower courts rejected Thomas’s proposed extension of
Collins because Thomas was not without a remedy—he could,
and did, recover from his landlords.
    The Wisconsin Supreme Court reversed, holding that
Thomas’s case was similar enough to Collins’s case to warrant
application of the risk-contribution theory. Id. at 557. As in
Collins, the pigment manufacturers contributed to the risk of
injury to the public by producing or marketing a harmful
product. They were also better positioned to absorb the costs
of the injuries. And, like Collins, Thomas could not identify
“the precise manufacturer of the white lead carbonate that
caused his injuries.” Id. at 559. On this point, the court rejected
the manufacturers’ argument that white lead carbonate—
which came in three diﬀerent chemical formulas—was not
fungible. It held that chemical identity was not necessary for
fungibility. The court reasoned that a product could be “fun-
gible” in three diﬀerent senses: (1) functionally interchangea-
ble; (2) physically indistinguishable; or (3) uniform in risk
level. Id. at 560–61. The court concluded that, when viewing
8                                               Nos. 20-1774 et al.

the factual record in the light most favorable to Thomas, white
lead carbonate was fungible in all three senses.
    The court proceeded to reject the manufacturers’ other ar-
guments as to why Collins should not apply. First, the “dras-
tically larger” window of liability—potentially several dec-
ades or more, depending on when a house was built—was not
a reason to let the pigment manufacturers oﬀ the hook. “[T]he
Pigment Manufacturers’ argument must be put into perspec-
tive: they are essentially arguing that their negligent conduct
should be excused because they got away with it for too long.”
Id. at 562. Next, the court rejected the argument that Collins
should not apply because lead poisoning had multiple poten-
tial causes and did not produce a “signature injury.” While it
agreed with the argument’s premises, the court reasoned that
these were issues for the jury. Id. at 563. Finally, the court re-
jected the argument that Collins should not apply because the
pigment manufacturers were not in exclusive control of the
risk that their product created:
      [A]s doctors were the ones who prescribed the dosage
      of DES, so too were the paint manufacturers that mixed
      the amount of white lead carbonate in the paint. How-
      ever, the paint did not alter the toxicity of the white
      lead carbonate anymore than the pharmacist did by
      ﬁlling a prescription. To the contrary, at best, the paint
      manufacturers actually diluted the white lead car-
      bonate’s toxicity. In other words, the inherent danger-
      ousness of the white lead carbonate pigment existed
      the moment the Pigment Manufacturers created it.
Id.
Nos. 20-1774 et al.                                              9

    The Wisconsin Supreme Court then set forth the elements
of both negligence and strict liability claims for white lead car-
bonate plaintiﬀs. As in Collins, Thomas’s burden was relaxed
“only with respect to establishing the speciﬁc type of DES the
plaintiﬀ’s mother took, which, in this case, translates into the
speciﬁc type of white lead carbonate Thomas ingested.” Id.
Thomas only had to “prove that the Pigment Manufacturers
produced or marketed white lead carbonate for use during
the relevant time period: the duration of the houses’ exist-
ence.” Id. at 564. If Thomas could make out a prima facie case,
the burden would shift to the defendant to prove “that it did
not produce or market white lead carbonate either during the
relevant time period or in the geographical market where the
house is located.” Id. Unlike in Collins, moreover, the pigment
manufacturers might have additional defenses, “including
that lead poisoning could stem from any number of sub-
stances (since lead itself is ubiquitous) and that it is diﬃcult
to know whether Thomas’s injuries stem from lead poisoning
as they are not signature injuries.” Id. at 564–65.
    Two Justices dissented, expressing dismay that the pig-
ment manufacturers could be “held liable for a product they
may or may not have produced, which may or may not have
caused the plaintiﬀ’s injuries, based on conduct that may have
occurred over 100 years ago when some of the defendants
were not even part of the relevant market.” Id. at 567–68 (Wil-
cox, J., dissenting); see also id. at 590 (Prosser, J., dissenting)
(“[T]his court has now created a remedy for lead paint poi-
soning so sweeping and draconian that it will be nearly im-
possible for paint companies to defend themselves or, frankly,
for plaintiﬀs to lose.”).
10                                            Nos. 20-1774 et al.

     3. Godoy
    In Thomas, the Wisconsin Supreme Court made clear that
it was not reaching the merits of Thomas’s claim, but only de-
ciding whether he was eligible to rely on the risk-contribution
theory. See id. at 528–29 nn.2 & 4. A few years after Thomas, the
court had occasion to consider the merits of a white lead car-
bonate claim. See Godoy ex rel. Gramling v. E.I. du Pont de
Nemours & Co., 768 N.W.2d 674 (Wis. 2009). Like Thomas, Ru-
ben Baez Godoy sustained lead poisoning after he ingested
white lead carbonate in his childhood home. Proceeding un-
der Thomas, Godoy sued several manufacturers of white lead
carbonate, asserting both negligence and strict liability claims.
His legal theory was that white lead carbonate was defectively
designed.
   As an initial matter, the court rejected Godoy’s argument
that the product in question was actually “residential paint
pigment.” Id. at 682. For one thing, Godoy’s complaint fo-
cused exclusively on “white lead carbonate.” Id. Plaintiﬀs in
products liability cases, the court explained, “must—at mini-
mum—identify the product alleged to be defective.” Id. “Do-
ing so puts the defendant on notice and allows the defendant
to begin building a defense.” Id. More fundamentally, the
product at issue could not be residential paint pigment be-
cause the risk-contribution theory applied only to “fungible
and identically defective” products. Id. In Thomas, that prod-
uct was white lead carbonate pigment. The court made clear
that it had never applied the risk contribution theory to “res-
idential paint pigment,” or to “paint containing white lead
carbonate.” Id. at 683 & n.10.
  On the merits, the court rejected Godoy’s argument that
white lead carbonate was defectively designed. The court
Nos. 20-1774 et al.                                           11

explained that Wisconsin courts had “discussed three catego-
ries of product defects—manufacturing defects, design de-
fects, and defects based on a failure to adequately warn.” Id.
at 683. Godoy’s negligence and strict liability claims rested on
a design defect, meaning “the design itself is the cause of the
unreasonable danger.” Id. at 683–84. Godoy’s theory of design
defect was that the presence of lead rendered white lead car-
bonate defectively designed. The court disagreed: “A claim
for defective design cannot be maintained where the presence
of lead is the alleged defect in design, and its very presence is
a characteristic of the product itself. Without lead, there can
be no white lead carbonate pigment.” Id. at 685. Although Go-
doy’s negligence and strict liability claims were “separate av-
enues of recovery,” they both failed on this ground. See id. at
681 n.7.
   4. Wisconsin Statute § 895.046 & Gibson
    In 2011, the Wisconsin legislature passed Wis. Stat.
§ 895.046, which eﬀectively overruled Thomas while preserv-
ing Collins. The statute reinstates ordinary causation princi-
ples in all products liability cases, while carving out a narrow
exception for plaintiﬀs like Collins who have no other remedy
and whose injuries stem from a “complete[ly] integrated
product” produced in “chemically and physically identical”
forms and sold in generic packaging. § 895.046(4). In 2013, the
legislature amended § 895.046 to make it retroactive. See
§ 895.046(2). The statute “assures that businesses may con-
duct activities in this state without fear of being sued for in-
deﬁnite claims of harm from products which businesses may
never have manufactured, distributed, sold, or promoted, or
which were made and sold decades ago.” § 895.046(1g). To
12                                            Nos. 20-1774 et al.

that end, the statute also includes certain time limits and join-
der requirements. § 895.046 (4)(b), (5).
    In Gibson v. American Cyanamid Co., 760 F.3d 600 (7th Cir.
2014), we considered whether applying § 895.046 retroac-
tively to extinguish already pending white lead carbonate
claims would violate the Wisconsin Constitution’s due pro-
cess guarantee. Applying the Wisconsin Supreme Court’s
two-step framework, we held that it would. Id. at 609. First,
Gibson had “a ‘vested right’ in his claims under Thomas’s risk-
contribution theory.” Id. Second, § 895.046 lacked a rational
basis because the private interest at stake outweighed the
public interest that the statute promoted. Id. at 609–10. At both
steps of the analysis, we held that Wisconsin Supreme Court
precedent “dictate[d]” our conclusions. Id. (citing Matthies v.
Positive Safety Mfg. Co., 628 N.W.2d 842, 861 (Wis. 2001) (hold-
ing unconstitutional the retroactive application of a statute ex-
tinguishing the right to recover on a common law negligence
claim under an unmodiﬁed doctrine of joint and several lia-
bility); Martin by Scoptur v. Richards, 531 N.W.2d 70, 93 (Wis.
1995) (holding unconstitutional the retroactive application of
a statute extinguishing the right to recover an unlimited
amount of non-economic damages)). We went on to hold that
Thomas did not violate the Federal Constitution. Gibson, 760
F.3d at 627.
    Following our decision in Gibson, the Wisconsin Supreme
Court split 3–3 (with one Justice not participating) on the ﬁrst
issue we addressed in Gibson: whether retroactively applying
§ 895.046 to white lead carbonate claims would violate the
Wisconsin Constitution’s due process guarantee. Clark ex rel.
Gramling v. Am. Cyanamid Co., 877 N.W.2d 117 (Wis. 2016).
Nos. 20-1774 et al.                                          13

B. Factual and Procedural Background
    This legal background sets the stage for this case. The net
eﬀect of Thomas, § 895.046, and Gibson was a six-year window
(2005–2011) in which plaintiﬀs in Wisconsin could rely on the
risk-contribution theory to sue white lead carbonate manufac-
turers for injuries arising from their ingestion of white lead
carbonate as children. Approximately 170 such lawsuits were
ﬁled. The three plaintiﬀs here were the ﬁrst to go to trial. The
parties selected their cases as “bellwethers” for the other
cases, which remain pending before the district court.
   1. The Plaintiﬀs’ Claims
    The sad sequence of events leading to the plaintiﬀs’ claims
will by now look familiar. As young children in the 1990s or
early 2000s, Glenn Burton, Jr., Ravon Owens, and Cesar
Sifuentes lived in Milwaukee homes (built between 1899 and
1922) that had paint containing white lead carbonate. While
they were young children, the plaintiﬀs had elevated blood
lead levels ranging from 31 (Burton) to 48 (Sifuentes) to 53
(Owens) micrograms per deciliter at their peak. For context,
Wisconsin currently deﬁnes lead poisoning as “a level of lead
in the blood of 5 or more micrograms per [deciliter] of blood.”
Wis. Stat. § 254.11(9). (This number has steadily decreased
over time.) Sifuentes and Owens were hospitalized and re-
ceived chelation therapy to reduce their blood lead levels.
    Relying on Wisconsin’s risk-contribution theory, the
plaintiﬀs—who could not identify the manufacturer of the
white lead carbonate in their childhood homes—sued six
white lead carbonate manufacturers for both negligence and
strict liability, seeking to hold them liable for brain damage
and other injuries resulting from their ingestion of white lead
14                                          Nos. 20-1774 et al.

carbonate as young children. The plaintiﬀs ﬁled their lawsuits
separately, but the district court consolidated them for trial.
     2. The Defendants’ Production of White Lead Carbonate
    Only three of the defendants below are parties to this ap-
peal: DuPont, Sherwin-Williams, and Armstrong. The plain-
tiﬀs sued Armstrong in its capacity as successor-in-interest to
the John R. MacGregor Lead Company. The three defendants
below who are not parties to this appeal are: American Cyan-
amid Company, NL Industries, Inc. (formerly known as the
National Lead Company), and the Atlantic Richﬁeld Com-
pany. As explained below, the district court dismissed Amer-
ican Cyanamid for lack of personal jurisdiction, National
Lead settled, and the jury found Atlantic Richﬁeld not liable.
    DuPont, Sherwin-Williams, and Armstrong each manu-
factured white lead carbonate for a period in the twentieth
century. DuPont manufactured white lead carbonate at a fac-
tory in Philadelphia from 1917 to 1924. It incorporated its
white lead carbonate into in its own paint products, which in-
cluded ready-mixed paint and white lead-in-oil—a paste
commonly sold to “master painters” who combined it with
other ingredients to make their own paint. During this period,
DuPont sold some of its ready-mixed paint products in Mil-
waukee through a wholesaler. After it stopped making white
lead carbonate in 1924, DuPont continued making and selling
paint products containing white lead carbonate manufac-
tured by other companies until 1966. From 1925 to 1946, Na-
tional Lead manufactured white lead-in-oil for DuPont. As
part of this arrangement, DuPont supplied National Lead
with the ingredients and speciﬁcations for manufacturing
white lead-in-oil. DuPont then sold the ﬁnished white lead-
in-oil under its own brand name.
Nos. 20-1774 et al.                                         15

   Sherwin-Williams manufactured white lead carbonate
from 1910 to 1947 and used its white lead carbonate as an in-
gredient in its own paint products. Sherwin-Williams had a
presence in the Milwaukee market during this time. Apart
from its own white lead carbonate manufacturing, Sherwin-
Williams sold products containing other companies’ white
lead carbonate pigment from 1880 to 1969. In 1955, Sherwin-
Williams began including warnings about the dangers of in-
gesting lead on some of its lead-based paints.
    MacGregor (Armstrong’s predecessor-in-interest) manu-
factured white lead carbonate at a plant in Chicago from 1938
to 1971. MacGregor used its white lead carbonate as an ingre-
dient in its “Scotch Laddie” line of paint. Scotch Laddie paint
appeared in advertisements and telephone directories in Mil-
waukee between 1957 and 1971. MacGregor also sold its white
lead carbonate to other paint manufacturers for use in their
paint products.
   3. Pretrial Rulings
    The district court made three signiﬁcant pretrial rulings
that shaped the trial. First, the court granted summary judg-
ment to Sherwin-Williams and Armstrong on the plaintiﬀs’
negligent failure-to-warn claims. The court reasoned that the
plaintiﬀs’ caregivers already knew that lead pigment was
dangerous and needed no further warning. The court pointed
out that Sherwin-Williams and other paint manufacturers
started issuing product warnings in 1955—long before the
plaintiﬀs were exposed in the 1990s or early 2000s. Meanwhile
federal, state, and local governments began warning of the
risks of lead-based paint in homes in the 1970s. The plaintiﬀs’
caregivers even testiﬁed at their depositions that they knew,
before the plaintiﬀs’ exposure to lead-based paint, that
16                                            Nos. 20-1774 et al.

children should not eat paint chips because of the risk of lead
exposure. For these reasons, the defendants had no duty to
warn as a matter of law. Still, the court ruled that the plaintiﬀs
could pursue negligence claims “based on the general duty of
ordinary care.”
     Second, the court largely denied Sherwin-Williams’s and
Armstrong’s motions for summary judgment on the plain-
tiﬀs’ strict liability failure-to-warn claims. The court began by
distinguishing between duty to warn in the negligence and
strict liability contexts, reasoning that negligence requires a
duty to warn the plaintiﬀ whereas strict liability requires a
duty to warn the “ordinary consumer” who purchased or
used white lead carbonate or paint containing white lead car-
bonate when the defendants put those products on the mar-
ket. The court found a genuine issue of material fact as to
whether the defendants had a duty to warn these ordinary
consumers. At the same time, the court ruled as a matter of
law that the defendants had no duty to warn in their capacity
as pigment manufacturers who merely sold pigment to other
companies or master painters. The court explained: “It makes
little sense for the [white lead carbonate] manufacturer to owe
a duty to warn the consumer at the moment that the pigment
is delivered to the paint manufacturer, because the [white
lead carbonate] manufacturer has no eﬀective means of com-
municating that warning.” The court thus granted summary
judgment to the defendants on the plaintiﬀs’ strict liability
failure-to-warn claims to the extent that the defendants sup-
plied white lead carbonate to other companies.
    Third, less than six weeks before trial, the court denied
DuPont’s motion to exclude evidence of its post-1924 con-
tracts to purchase white lead-in-oil from National Lead. It also
Nos. 20-1774 et al.                                          17

denied Sherwin-Williams’s motion to exclude evidence of its
production or promotion of paint products containing an-
other company’s white lead carbonate. The court reasoned
that Thomas contemplated liability for producing or “market-
ing” white lead carbonate and selling products that contained
another company’s white lead carbonate amounted to “mar-
keting” white lead carbonate. The defendants moved for re-
consideration, arguing that the court’s ruling contradicted
Thomas, Godoy, the plaintiﬀs’ longstanding theory of the case,
and the court’s prior rulings. In the alternative, they moved to
continue trial and reopen discovery so that they could pre-
pare a defense according to this broader theory of liability.
The court denied these motions, reasoning that Thomas put
them on notice that they could be liable for marketing paint
products containing another company’s white lead carbonate.
    The court also made several other relevant pretrial rulings:
It granted summary judgment to the plaintiﬀs on the issues of
whether white lead carbonate was “fungible” and whether
Armstrong was the successor-in-interest to MacGregor. It de-
nied summary judgment to Sherwin-Williams and Armstrong
on the issue of whether § 895.046 barred the plaintiﬀs’ claims.
It denied the defendants’ motion to exclude the testimony of
two of the plaintiﬀs’ experts: Dr. Idit Trope and Dr. James Be-
sunder. And it denied Sherwin-Williams’s motion to exclude
evidence and arguments about its constitutionally protected
product advertisements and association with industry
groups.
    National Lead settled before trial. This was a signiﬁcant
development because, as the district court explained,
“[p]laintiﬀs and defendants alike understand National Lead
to have been a leading manufacturer of [white lead carbonate]
18                                            Nos. 20-1774 et al.

pigment with a signiﬁcant presence in the Milwaukee market
during the ﬁrst half of the Twentieth Century.” National Lead
settled pursuant to a “Pierringer release,” according to which
“a tort plaintiﬀ settles with a tortfeasor, reserves its right to
pursue claims against other joint tortfeasors, and agrees to in-
demnify the settling tortfeasor for any claims for contribution
that non-settling tortfeasors might bring against the settling
tortfeasor.” Bruner Corp. v. R.A. Bruner Co., 133 F.3d 491, 494
(7th Cir. 1998) (citing Pierringer v. Hoger, 124 N.W.2d 106 (Wis.
1963)).
    On its own initiative, and over the defendants’ objections,
the court bifurcated the trial into two phases: a liability phase
and an apportionment phase. Relying on Collins, the court ex-
plained that phase one would yield a “pool of defendants”
that could have caused the plaintiﬀs’ injuries. Phase one
would also determine the plaintiﬀs’ overall damages. Phase
two would focus on allocating the damages based on equita-
ble factors like market share and the defendants’ respective
roles in the industry. See Collins, 342 N.W.2d at 52–53. The
court then made the related decision to exclude evidence of
National Lead’s market share and role in the Milwaukee mar-
ket from phase one, ﬁnding that such evidence would be con-
fusing, irrelevant, and prejudicial. As the court explained,
“National Lead’s unusual position as a settled defendant
whose liability and proportional responsibility remained live
issues presented signiﬁcant legal and evidentiary issues.”
While National Lead’s large market share in Milwaukee was
relevant to the allocation of damages, it was irrelevant to
whether other defendants were present in the Milwaukee
market. Meanwhile, it would be all too easy for other defend-
ants to point the ﬁnger at National Lead during the liability
phase in hopes of exculpating themselves entirely.
Nos. 20-1774 et al.                                             19

   4. Trial
    The cases proceeded to trial against the remaining ﬁve de-
fendants. The plaintiﬀs went to trial on the two claims that
had survived summary judgment: ordinary negligence and
strict liability failure-to-warn. To prove their claims, the plain-
tiﬀs presented evidence of the dangers of lead-based paint to
young children; awareness and recognition of these dangers
among the medical and scientiﬁc communities, the paint in-
dustry, and the defendants speciﬁcally; the defendants’ con-
tinued production, marketing, promotion, and advertisement
of white lead carbonate and products containing white lead
carbonate; and the plaintiﬀs’ childhood ingestion of white
lead carbonate and subsequent injuries.
    To prove their injuries, the plaintiﬀs relied largely on the
expert testimony of Dr. Trope and Dr. Besunder. Dr. Trope, a
neuropsychologist, performed neuropsychological evalua-
tions on each plaintiﬀ and concluded that each had neuropsy-
chological impairments indicating brain damage. She ex-
plained that a neuropsychological evaluation gauges brain
function by testing various “domains” such as cognitive abil-
ity, language functioning, visual motor functioning, memory,
attention and concentration, and executive functions like
judgment, organization, conceptualization, and information
processing. She testiﬁed that abnormally large discrepancies
across the plaintiﬀs’ functional domains led her to conclude
that each plaintiﬀ had brain damage. On cross-examination,
Dr. Trope testiﬁed that the plaintiﬀs’ history of lead poisoning
was a substantial contributing factor to their neuropsycholog-
ical dysfunction. The plaintiﬀs objected during this cross-ex-
amination that they had not oﬀered Dr. Trope to prove causa-
tion.
20                                            Nos. 20-1774 et al.

    Dr. Besunder, a pediatric critical care physician and toxi-
cologist who treats children with lead poisoning, testiﬁed to
the fact, source, and extent of each of the plaintiﬀs’ injuries.
Dr. Besunder did not personally evaluate any of the plaintiﬀs.
Instead, he relied on Dr. Trope’s neuropsychological evalua-
tions and general epidemiological studies on the eﬀects of
lead poisoning in children. Relying on the neuropsychologi-
cal evaluations, Dr. Besunder testiﬁed that each of the plain-
tiﬀs had brain damage. Like Dr. Trope, Dr. Besunder based
this conclusion on “signiﬁcant deviations” in the plaintiﬀs’
functional domains. Dr. Besunder further testiﬁed that lead
poisoning caused plaintiﬀs’ brain damage. He explained that
the plaintiﬀs’ functional deﬁcits were consistent with patterns
of brain damage in lead-poisoned children documented by
the medical and scientiﬁc literature. He testiﬁed that he had
reviewed the plaintiﬀs’ medical records to rule out other po-
tential causes of their brain damage.
     Finally, Dr. Besunder attempted to quantify the plaintiﬀs’
brain damage. He testiﬁed that each of the plaintiﬀs had lost
at least 10 IQ points due to lead poisoning. He explained that
“several studies” had “attempted to quantitate the impact of
lead levels up to approximately 20 to 30 micrograms per dec-
iliter” and “all those studies have very similar results, that by
the time your leads level is approaching the 25 to 30 range that
child has lost approximately 10 IQ points.” He testiﬁed that
children with blood lead levels above 30 would have lost ad-
ditional IQ points, but he stuck with the “conservative esti-
mate of 10 IQ points” because “the medical literature will only
allow me to give an approximate quantitative estimate for
lead levels up to 30.” He explained that the studies he relied
on controlled for alternative causes. He conceded, however,
Nos. 20-1774 et al.                                             21

that he had not published his methodology for quantifying IQ
loss and that he did not have a baseline IQ for the plaintiﬀs.
    The defendants’ primary line of defense at trial was
“chemical exculpation.” Each of the defendants called experts
to testify to diﬀerences in the chemical composition of the
paint samples taken from the plaintiﬀs’ childhood homes and
the defendants’ residential paint formulas.
     At the close of evidence, the court dismissed American Cy-
anamid for lack of personal jurisdiction. The court submitted
the plaintiﬀs’ case against the other four defendants to the
jury. The jury found DuPont, Sherwin-Williams, and Arm-
strong liable on both claims. It awarded $2 million in damages
to each of the plaintiﬀs. The jury found Atlantic Richﬁeld not
liable. The trial never reached phase two—where the jury
would have apportioned the damages among the defend-
ants—because the three defendants found liable chose to set-
tle, assigning 12.5% of fault to National Lead and splitting the
rest among themselves on a joint and several basis.
   5. Post-Trial Rulings
    The defendants ﬁled various post-trial motions. They each
moved for judgment notwithstanding the verdict, arguing
that Wisconsin’s judicial public policy factors precluded their
liability. See Fandrey ex rel. Connell v. Am. Family Mut. Ins. Co.,
680 N.W.2d 345, 350 (Wis. 2004). They also moved for a new
trial, challenging the court’s pretrial legal rulings, the suﬃ-
ciency of the evidence, and the court’s decision to bifurcate
the trial. Sherwin-Williams and Armstrong moved for judg-
ment as a matter of law on similar grounds.
   The court denied the defendants’ post-trial motions, with
one exception: it agreed to remit Burton’s damages award
22                                           Nos. 20-1774 et al.

from $2 million to $800,000 because Dr. Besunder admitted
during trial that, of the 10 IQ points that Burton lost due to
lead poisoning, he lost six of them before he moved to the
home that he focused on at trial.
     The defendants now appeal.
                        II. Discussion
    The defendants raise a host of challenges on appeal. We
focus primarily on three foundational issues concerning the
scope of Wisconsin products liability law and the defendants’
corresponding potential for liability. First, all three defend-
ants argue that the district court improperly extended Thomas
by allowing the jury to ﬁnd them liable in their capacity as
paint manufacturers, rather than white lead carbonate manu-
facturers. Second, Sherwin-Williams argues that the court er-
roneously allowed the jury to ﬁnd it liable on the negligence
claims without proof of a product defect. Third, Sherwin-Wil-
liams and Armstrong contend that the court erroneously al-
lowed the jury to ﬁnd them liable on the strict liability claims
in the absence of a duty to warn or any proof that the lack of
a warning caused the plaintiﬀs’ injuries. Our review of Wis-
consin law convinces us that the defendants are correct on all
three counts. We see no merit in the defendants’ remaining
challenges, with one exception: we hold that the court abused
its discretion in admitting Dr. Besunder’s testimony about the
plaintiﬀs’ IQ loss.
A. The Risk-Contribution Theory
    We begin with the defendants’ challenge to the court’s ap-
plication of the risk-contribution theory. The defendants ar-
gue that the district court improperly extended Thomas by al-
lowing the plaintiﬀs to hold them liable in their capacity as
Nos. 20-1774 et al.                                                 23

manufacturers of ﬁnished paint products, and not just in their
capacity as manufacturers of white lead carbonate.
    The district court denied the defendants’ motions in
limine on this point, ruling that the plaintiﬀs could introduce
evidence of the defendants’ production or sale of paint con-
taining another company’s white lead carbonate. The court
stood by its pretrial ruling when denying the defendants’ mo-
tions for a new trial. We review both rulings for abuse of dis-
cretion. Turubchuk v. S. Ill. Asphalt Co., Inc., 958 F.3d 541, 548–
49 (7th Cir. 2020). An evidentiary ruling that rests on a legal
error is, by deﬁnition, an abuse of discretion. United States v.
Chaparro, 956 F.3d 462, 474 (7th Cir. 2020). We will grant a new
trial only if “the verdict is against the weight of the evidence,
the damages are excessive, or if for other reasons the trial was
not fair to the moving party.” Pickett v. Sheridan Health Care
Ctr., 610 F.3d 434, 440 (7th Cir. 2010) (quoting Emmel v. Coca-
Cola Bottling Co. of Chi., 95 F.3d 627, 636 (7th Cir. 1996)). Evi-
dentiary errors warrant a new trial “if the evidentiary errors
had ‘a substantial and injurious eﬀect or inﬂuence on the de-
termination of a jury and the result is inconsistent with sub-
stantial justice.’” Fields v. City of Chi., 981 F.3d 534, 544 (7th Cir.
2020) (quoting Lewis v. City of Chi. Police Dep’t, 590 F.3d 427,
440 (7th Cir. 2009)).
   As set forth above, each of the defendants was both a white
lead carbonate manufacturer and a manufacturer of ﬁnished
paint products at various points in the twentieth century.
They maintain that the risk-contribution theory applies to
them only in their capacity as manufacturers of white lead
carbonate. We agree; the Wisconsin Supreme Court has ex-
pressly limited the risk-contribution theory to manufacturers
of white lead carbonate.
24                                            Nos. 20-1774 et al.

     1. Scope of Thomas
    In Thomas, the court invariably referred to the defendants
as “pigment manufacturers.” The court used this term when
setting forth the elements of Thomas’s cause of action. Thomas,
701 N.W.2d at 564. At one point, the court even drew a critical
distinction between “pigment manufacturers” and “paint
manufacturers.” The pigment manufacturers in Thomas had
argued that they should not be liable because they “were not
in exclusive control of the risk their product created ...” Id. at
563. In other words, the pigment manufacturers attempted to
shift the blame to paint manufacturers—the companies that
sold lead-based paints directly to consumers. The court re-
jected this argument. In doing so it analogized paint manu-
facturers to DES prescribers: while paint manufacturers
mixed white lead carbonate into paint, they “did not alter the
toxicity of the white lead carbonate anymore than the phar-
macist did by ﬁlling a prescription.” Id. If anything, “the paint
manufacturers actually diluted the white lead carbonate’s tox-
icity.” Id. (emphasis added). “[T]he inherent dangerousness
of the white lead carbonate pigment existed the moment the
Pigment Manufacturers created it.” Id. (emphasis added).
    We noted the signiﬁcance of this passage in Gibson. In re-
jecting the argument that Thomas had discriminated against
out-of-state corporations by imposing the risk-contribution
theory against out-of-state pigment manufacturers but not in-
state paint makers and retailers, we commented: “This argu-
ment makes an inferential leap too far, and also ignores
Thomas’s discussion of pigment manufacturers’ greater culpa-
bility, when compared to paint makers and retailers.” Gibson,
760 F.3d at 627 n.11 (describing Thomas as holding that “if
Nos. 20-1774 et al.                                          25

anything, paint makers and retailers reduced the risk of harm
by diluting the lead pigment”).
    Finally, Godoy conﬁrmed that the risk-contribution theory
applies only to white lead carbonate pigment. The lower court
had “mistakenly stated” that the product in Thomas was
“paint containing white lead carbonate.” Godoy, 768 N.W.2d
at 682 n.10. The Wisconsin Supreme Court was clear: “This
statement misconstrues our holding in Thomas.” Id. Similarly,
the court rejected Godoy’s argument that the risk-contribu-
tion theory could apply to “residential paint pigment.” Id. at
683.
    In short, the Wisconsin Supreme Court has held that the
risk-contribution theory applies to white lead carbonate manu-
facturers to the extent that they manufacture white lead car-
bonate. Applying risk contribution to paint manufacturers or
ﬁnished paint products would extend Thomas beyond its
bounds. See Thomas, 701 N.W.2d at 570 (Wilcox, J., dissenting)
(“It is important to emphasize that the industry defendants
are being sued in their capacity as manufacturers of white
lead carbonate and not the ﬁnished product, paint.”).
    Admittedly, distinguishing between pigment manufactur-
ers and paint manufacturers—and between pigment and
paint—can be confusing because pigment does not reach res-
idential consumers unless paint manufacturers sell them a ﬁn-
ished paint product. Moreover, many companies, including
the defendants here, historically manufactured both pigment
and ﬁnished paint products. Still, the Wisconsin Supreme
Court has made clear that such companies are liable under the
risk-contribution theory only in their capacity as manufactur-
ers of white lead carbonate pigment. As a practical matter, this
means that a paint manufacturer cannot be liable under the
26                                           Nos. 20-1774 et al.

risk-contribution theory for selling a ﬁnished product that
contains another company’s white lead carbonate. Only the
manufacturer of the white lead carbonate can be liable.
    Sherwin-Williams and Armstrong blur the issue by argu-
ing that they cannot be held liable as paint manufacturers
even if they sold paint containing their own white lead car-
bonate. This argument is technically correct but inconsequen-
tial. Under Thomas, a company that manufactures white lead
carbonate can be liable under the risk-contribution theory if
its white lead carbonate could have injured the plaintiﬀ. 701
N.W.2d at 565. It does not matter how the white lead car-
bonate reached the plaintiﬀ—whether through the same com-
pany’s paint or another company’s paint. See id. at 563 (reject-
ing the pigment manufacturers’ argument that they could not
be liable because paint manufacturers altered their products
before they reached the residential consumers). Either way,
risk contribution applies because the company manufactured
white lead carbonate that could have injured the plaintiﬀ. To
the extent that Sherwin-Williams and Armstrong suggest that
a company can avoid liability entirely under the risk-contri-
bution theory by fully integrating its products and only sell-
ing white lead carbonate as an ingredient in its own paints,
that argument is nonsensical and has no basis in Thomas.
    The district court based its more expansive reading of
Thomas on the Wisconsin Supreme Court’s use of the word
“marketed.” As the district court saw it, a company that sells
lead-based paint is “marketing” lead pigment, even if it is not
“producing” it. Thus, the court reasoned, a paint manufac-
turer could be liable for selling paint containing another com-
pany’s white lead carbonate. We disagree. For one thing, this
is a strained interpretation of “marketing” in this context. A
Nos. 20-1774 et al.                                           27

bookseller does not “market” paper, even though paper is a
component of books. More fundamentally, Thomas foreclosed
this broad conception of “marketing” because it drew a dis-
tinction between pigment manufacturers and paint manufac-
turers and limited its holding to the former. If selling a ﬁn-
ished product qualiﬁed as “marketing” one of the product’s
ingredients, a company that had never manufactured pig-
ment could be liable under Thomas. Yet Thomas carefully lim-
ited its holding to “pigment manufacturers,” and Godoy rein-
forced that limitation. Thomas’s reference to “marketing”
must be read in context. Thomas speaks of “pigment manufac-
turers” that produce or market white lead carbonate. Thomas,
701 N.W.2d at 564. It must be the “pigment manufacturers”
doing the producing or marketing—not paint manufacturers
or anyone else.
    For these reasons, we hold that the district court ex-
tended—and did not merely apply—the holding of Thomas.
We further hold that the court’s extension of Thomas was a le-
gal error. The plaintiﬀs do not dispute that the key feature of
DES and white lead carbonate—fungibility—does not carry
over to paint, so the core rationale of Collins and Thomas is in-
applicable to paint and paint manufacturers. See Godoy, 768
N.W.2d at 682–83. Apart from that, Wis. Stat. § 895.046 for-
bade the district court’s extension of Thomas. To be sure, Gib-
son holds that § 895.046 may not retroactively extinguish the
cause of action that Thomas recognized. But the plaintiﬀs’
claims in this case went beyond Thomas. The plaintiﬀs had a
vested right to Thomas; they did not have a vested right to ex-
tend Thomas.
28                                                  Nos. 20-1774 et al.

     2. Prejudice
    The court’s error requires a new trial because it signiﬁ-
cantly expanded the scope of the defendants’ potential liabil-
ity and the evidence at trial. It also deprived the defendants
of the opportunity to build an appropriate defense. See Godoy,
768 N.W.2d at 682–83. For years, the defendants had litigated
under the (valid) assumption that they were liable only in
their capacity as pigment manufacturers. Less than six weeks
before trial, however, the defendants learned for the ﬁrst time
that they were also subject to liability as manufacturers of
paint products containing white lead carbonate. The court’s
last-minute, legally incorrect ruling left them scrambling to
adapt their defenses to the plaintiﬀs’ newly enlarged theory
of liability.
   Consider the prejudice to DuPont. DuPont manufactured
white lead carbonate for a narrow seven-year period (1917 to
1924). The court’s erroneous legal ruling enlarged DuPont’s
potential window of liability from that seven-year period to a
nearly ﬁfty-year period (1917 to 1966) during which DuPont
manufactured paint products containing white lead car-
bonate. 2
    In keeping with the court’s pretrial ruling, the plaintiﬀs
introduced evidence of DuPont’s post-1924 knowledge and
conduct and asked the jury to ﬁnd DuPont liable for its actions
through 1966. They also seized on weaknesses in DuPont’s
primary defense that resulted directly from the court’s erro-
neous ruling. Through no fault of its own, DuPont was

     2
     The plaintiﬀs suggest that DuPont manufactured white lead car-
bonate until 1946. But the only evidence they cite indicates that National
Lead manufactured white lead-in-oil for DuPont during those years.
Nos. 20-1774 et al.                                            29

unprepared to rebut these attacks. The court’s late-stage rul-
ing meant that DuPont had to expand its chemical-exculpa-
tion defense to cover all the paint formulas that DuPont had
used during the additional 42 years (1924 to 1966) that were
now on the table. At trial, however, the court precluded
DuPont’s paint-chemistry expert from opining on any of
DuPont’s post-1924 paint formulas because DuPont had not
disclosed any of these opinions before trial. The plaintiﬀs took
full advantage of this gap in DuPont’s defense during closing
arguments. They argued that DuPont’s chemical-exculpation
defense failed because its expert “came into this courtroom
and oﬀered opinions on the years 1917 to 1924” when “you
saw that chart that indicated that they made white lead car-
bonate products up until 1966.”
   The prejudice was similar for Sherwin-Williams, whose
window of liability expanded from a 37-year period in the
ﬁrst half of the twentieth century (1910 to 1947) to a 90-year
period (1880 to 1969) during which it produced or marketed
paint products containing white lead carbonate.
    Armstrong is in a unique position because its predecessor-
in-interest MacGregor was both a pigment manufacturer and
a paint manufacturer at all relevant times. While it is still pos-
sible that the court’s error prejudiced Armstrong, Armstrong
has made no attempt on appeal to explain how that is so. In
the end, we need not resolve this issue because, as we explain
below, Armstrong (like Sherwin-Williams) is entitled to relief
on other grounds. DuPont is the only defendant that rests its
case on this issue. Given the prejudice we have described,
DuPont is entitled to a new trial on both claims that went to
trial.
30                                           Nos. 20-1774 et al.

     3. Gibson & Fungibility
    We reject the defendants’ other challenges to the court’s
application of the risk-contribution theory. First, Sherwin-
Williams and Armstrong ask us to overrule Gibson. They
claim that subsequent developments in the law have under-
mined Gibson’s analysis. The district court denied the defend-
ants’ motion for summary judgment on this point. We review
that ruling de novo, viewing the evidence in the light most
favorable to the non-moving party. Turubchuck, 958 F.3d at
548; see also Chemetall GMBH v. ZR Energy, Inc., 320 F.3d 714,
719 (7th Cir. 2003) (explaining that even after a trial we may
review an earlier denial of summary judgment if the motion
for summary judgment raised legal, and not factual, issues).
    We decline to revisit Gibson. When we weigh in on an un-
settled issue of state law, our conclusion binds us until the
state’s supreme court says otherwise. Reiser v. Residential
Funding Corp., 380 F.3d 1027, 1029–30 (7th Cir. 2004). The Wis-
consin Supreme Court has not said otherwise. In fact, it re-
cently split 3–3 on the very question that we addressed in Gib-
son. Clark, 877 N.W.2d 117. It would be hard to imagine better
evidence that an issue of state law remains unsettled. Moreo-
ver, the cases upon which we relied in Gibson remain good
law. See Matthies, 628 N.W.2d at 861; Martin, 531 N.W.2d at 93.
The defendants suggest that Lands’ End, Inc. v. City of Dodge-
ville, 881 N.W.2d 702 (Wis. 2016), rejected the balancing anal-
ysis that Gibson drew from Matthies and Martin. But Lands’ End
did not overrule or undermine either case. Only the concur-
rence questioned the “balancing test” that they applied. Id. at
733 (Ziegler, J., concurring). The defendants also cite Bank
Markazi v. Peterson, 136 S. Ct. 1310 (2016), but that separation
of powers case did not change Wisconsin law.
Nos. 20-1774 et al.                                             31

    Second, Armstrong argues that the district court erred in
ruling before trial that white lead carbonate was fungible as a
matter of law. It maintains that fungibility was a question for
the jury. The court resolved this issue at summary judgment,
so again our review is de novo, though we review the court’s
denial of a new trial on this basis for abuse of discretion.
Turubchuck, 958 F.3d at 548; see also Chemetall, 320 F.3d at 719.
    We easily reject Armstrong’s contention that fungibility is
a fact question for the jury to resolve. If fungibility were a fact
question, then Thomas would not have held that white lead
carbonate was fungible; it would have held instead that there
was a fact issue as to fungibility that precluded summary
judgment for the pigment manufacturers. Yet the court held,
on the record before it, that “white lead carbonate is fungi-
ble”—not merely that the pigment manufacturers were not
entitled to summary judgment. Thomas, 701 N.W.2d at 561.
That holding would make no sense if only the jury could de-
cide fungibility.
    The role of fungibility in the risk-contribution theory fur-
ther conﬁrms that it is a legal issue for the court. Fungibility
is a prerequisite to applying the risk-contribution theory. The
Wisconsin Supreme Court considers it when deciding
whether a plaintiﬀ lacks an adequate remedy at law, such that
the Wisconsin Constitution authorizes the court to develop
one. See Collins, 342 N.W.2d at 44–45; Thomas, 701 N.W.2d at
559–562. Judges, not juries, decide whether the plaintiﬀ has a
cause of action, and what that cause of action looks like. See
Paul F. Kirgis, The Right to a Jury Decision on Questions of Fact
Under the Seventh Amendment, 64 Ohio St. L.J. 1125, 1162 (2003)
(“[T]he judge always has the exclusive authority to decide
which questions should be asked.”). As a practical matter, it
32                                             Nos. 20-1774 et al.

would be rather bizarre if the parties had to go to trial just to
ﬁgure out what legal theory the plaintiﬀ could pursue. We
acknowledge that Wisconsin’s civil jury instructions list fun-
gibility as an element of a risk-contribution claim. Wis. JI—
Civil 3295. Like the district court, we conclude that the jury
instructions rest on an incorrect reading of Collins and Thomas.
    The harder question is whether Thomas established the
fungibility of white lead carbonate for future cases. The Wis-
consin Supreme Court has sent mixed signals on this ques-
tion. Collins stated ﬂatly that DES was fungible, without re-
gard to the facts of the case. 342 N.W.2d at 44. Thomas, by con-
trast, tied its fungibility determination to the facts of the case,
implying that its determination may not necessarily extend to
future cases. 701 N.W.2d at 559 n.47, 561. Godoy, meanwhile,
proclaimed that Thomas had established the fungibility of
white lead carbonate pigment as a matter of law: “In Thomas,
we concluded that for the purposes of risk-contribution, white
lead carbonate pigment is fungible, and all manufacturers of
white lead carbonate pigment could be held jointly and sev-
erally liable for injuries caused by the product.” Godoy, 768
N.W.2d at 683.
    We need not resolve this issue because, even if the fungi-
bility of white lead carbonate hinges on the facts of a particu-
lar case, Armstrong has not shown that the white lead car-
bonate in the plaintiﬀs’ homes was not fungible under any
deﬁnition that Thomas considered. Armstrong states, in con-
clusory fashion, that it presented evidence in the district court
that diﬀerent types of white lead carbonate have diﬀerent
chemical compositions and physical properties that permit
their identiﬁcation and alter their risk level. But Thomas re-
jected the argument that fungibility requires chemical
Nos. 20-1774 et al.                                            33

identity. 701 N.W.2d at 559. Even if Armstrong presented ev-
idence that the physical properties of white lead carbonate
vary, it does not explain what those variances are or why they
make manufacturer identiﬁcation any easier. As such, the
court properly resolved fungibility at summary judgment.
B. Negligence
   1. Product Defect
    Moving on, Sherwin-Williams alone argues that the dis-
trict court erred in ruling that the jury could ﬁnd it negligent
in the absence of a product defect. In its view, the court’s grant
of summary judgment to the defendants on the plaintiﬀs’ neg-
ligent failure-to-warn claims should have been the end of the
plaintiﬀs’ negligence claims, given that failure to warn was
the only product defect that the plaintiﬀs alleged.
    The district court denied Sherwin-Williams’s motion for
judgment as a matter of law on this point, ruling that Sherwin-
Williams could face liability “based on the general duty of or-
dinary care” even if its products were not defective. We re-
view the court’s ruling de novo. Turubchuk, 958 F.3d at 548.
Judgment as a matter of law is proper if “a reasonable jury
would not have a legally suﬃcient evidentiary basis to ﬁnd
for the party on that issue.” Fed. R. Civ. P. 50(a)(1). In apply-
ing this standard, we view the evidence in the light most fa-
vorable to the verdict. Turubchuk, 958 F.3d at 548.
    In Dippel v. Sciano, 155 N.W.2d 55 (Wis. 1967), the Wiscon-
sin Supreme Court adopted the products liability rule of the
Restatement (Second) of Torts § 402A (1965). Id. at 63. Section
402A supplies the elements of a strict products liability claim,
but its rule “is not exclusive, and does not preclude liability
based upon the alternative ground of negligence of the seller,
34                                            Nos. 20-1774 et al.

where such negligence can be proved.” Restatement (Second)
of Torts § 402A cmt. a; Godoy, 768 N.W.2d at 681 n.7.
    In recent years, many states have adopted the Third Re-
statement’s formulation of a products liability claim, which
“eschewed the doctrinal labels ‘strict liability’ and ‘negli-
gence’” and “deﬁned the categories functionally, according to
their required elements of proof.” Godoy, 768 N.W.2d at 681;
see also Restatement (Third) of Torts: Products Liability § 2
cmt. n (1998). In 2011, the Wisconsin legislature adopted the
Third Restatement’s rule, but only for strict liability claims.
See Wis. Stat. § 895.047. The plaintiﬀs here ﬁled suit before
2011, so the parties agree that § 895.047 does not apply to their
claims.
    Godoy explains the basic diﬀerences between strict liability
and negligence under Wisconsin products liability law. Strict
liability and negligence are “separate avenues of recovery”
with “substantively diﬀerent” elements. Godoy, 768 N.W.2d at
681 n.7. Strict liability “focuses on the nature of the defend-
ant’s product, whereas liability in negligence ‘hinges in large
part on the defendant’s conduct under circumstances involv-
ing a foreseeable risk of harm.’” Id. (quoting Green v. Smith &
Nephew AHP, Inc., 629 N.W.2d 727, 745 (Wis. 2001)); see also
Morden v. Cont’l AG, 611 N.W.2d 659, 673 (Wis. 2001); Greiten
v. LaDow, 235 N.W.2d 677, 683–86 (Wis. 1975) (controlling
opinion of Heﬀernan, J.).
     Despite these diﬀerences, the two claims have at least one
thing in common: “Both causes of action require a plaintiﬀ to
prove that the product causing injury was ‘defective.’” Godoy,
768 N.W.2d at 681 n.7 (citing Wis. JI—Civil 3200); accord Mor-
den, 611 N.W.2d at 673 (“The coexistence of the two theories
[i.e., negligence and strict liability] has sparked confusion and
Nos. 20-1774 et al.                                           35

criticism because both rely on an underlying product de-
fect.”). As for what constitutes a product defect, Godoy ex-
plains that “Wisconsin cases have discussed three categories
of product defects—manufacturing defects, design defects,
and defects based on a failure to adequately warn.” 768
N.W.2d at 683. Thus, a negligence claim must be predicated
on one of those three categories of product defects. See id. at
681 n.7, 683.
    We have acknowledged, as Morden did, that distinguish-
ing between strict liability claims and negligence claims in the
products liability context can be confusing. Insolia v. Philip
Morris Inc., 216 F.3d 596, 603 (7th Cir. 2000); Flaminio v. Honda
Motor Co., Ltd., 733 F.2d 463, 467 (7th Cir. 1984). Indeed, Wis-
consin’s continued distinction between the two claims has
generated signiﬁcant criticism. Morden, 611 N.W.2d at 673;
Sharp ex rel. Gordon v. Case Corp., 595 N.W.2d 380, 388 (Wis.
1999) (summarizing criticism but declining to overrule prece-
dent); Restatement (Third) of Torts: Products Liability § 2 cmt.
n (discussing the “mischief caused by dual instructions on
both negligence and strict liability”). We need not wade into
this debate. We do note, however, that the claims’ shared re-
quirement of a product defect has been at the heart of the crit-
icism. Morden, 611 N.W.2d at 673; see Sharp, 595 N.W.2d at 388;
Restatement (Third) of Torts: Products Liability § 2 cmt. n.
    Requiring a product defect for negligence claims makes
sense because otherwise a defendant might be found negli-
gent merely for making and selling a potentially dangerous
product. “It is boilerplate law that, merely because a product
or an operation is not as safe as possible, because there are
better methods of manufacture or performing an operation
does not lead to the conclusion that the method employed was
36                                            Nos. 20-1774 et al.

undertaken with a lack of ordinary care or the product was
defective.” Greiten, 235 N.W.2d at 685 (controlling opinion of
Heﬀernan, J.); see also Collins v. Ridge Tool Co., 520 F.2d 591,
594 (7th Cir. 1975) (“[A] manufacturer is under no duty to pro-
duce accident or fool-proof products. Neither is the manufac-
turer an insurer that its product is incapable of producing in-
jury.”) (citation omitted). Allowing a claim of negligence
without a product defect, as the district court did here, allows
a jury to ﬁnd the defendant negligent in the absence of any
actual negligence, whether in the design, manufacture, or
marketing of a product. There is a name for this type of liabil-
ity—it is called strict liability, not negligence. See Restatement
(Second) of Torts § 402A(2)(a) (allowing liability even if “the
seller has exercised all possible care in the preparation and
sale of his product”).
    The district court’s theory was that the defendants could
be found negligent because they continued to sell white lead
carbonate pigment for residential uses while knowing the
dangers that it posed to homeowners and their children. It
found support for this broad theory of liability in Judge
Learned Hand’s famous B159 F.2d 169, 173–74 (2d Cir. 1947). The
court reasoned that the jury could ﬁnd Sherwin-Williams neg-
ligent if the burden (B) of discontinuing the production and
sale of white lead carbonate pigment for residential uses was
outweighed by the probability (P) that children might ingest
it and suﬀer a serious injury or loss (L) as a result.
   Carroll Towing cannot do the heavy lifting that the district
court required of it. To begin, Wisconsin law governs this di-
versity case. We do not fault the court for looking to a foun-
dational federal case to help elucidate the principles
Nos. 20-1774 et al.                                          37

underpinning Wisconsin negligence law. But the court should
not have relied on Carroll Towing to create a pathway to liabil-
ity that Wisconsin courts had foreclosed. In any event, Carroll
Towing does not support the court’s theory of liability. Carroll
Towing was not a products liability case, and it certainly did
not hold that a company could be found negligent merely for
marketing a dangerous product. Critically, Carroll Towing in-
volved a negligent act: the defendant there was liable because
it left a barge unattended. Here there is no negligent act to
speak of, apart from Sherwin-Williams’s sale of a potentially
dangerous product. Given these distinctions, the court should
not have transposed the B717 N.W.2d 17, 28 (Wis. 2006). “Ordinary
care involves the concept of foreseeability, in that a reasonable
person exercising ordinary care would have foreseen injury
as a consequence of his act.” Id. at 29. “Whether a duty exists
under the circumstances, and the scope of any such duty, are
questions of law ….” Brenner v. Amerisure Mut. Ins. Co., 893
N.W.2d 193, 198 (Wis. 2017).
    Here, the court ruled that “the defendants owed a duty to
exercise ordinary care in manufacturing and marketing”
white lead carbonate for residential application because the
risks it posed to children were foreseeable. Contrary to Sher-
win-Williams’s arguments, the court did not predicate its rul-
ing on a general duty to the world at large. Sherwin-Williams
is also wrong to suggest that the court’s ﬁnding of a duty of
ordinary care conﬂicted with its ﬁnding that Sherwin-Wil-
liams had no duty to warn the plaintiﬀs. The duty to warn is
just one potential manifestation of the duty of ordinary care.
See Wis. JI—Civil 3200; see also Morden, 611 N.W.2d at 673–75.
In some circumstances, the duty of ordinary care requires a
40                                          Nos. 20-1774 et al.

warning. Here, the district court found that Sherwin-Williams
had no duty to warn for purposes of the plaintiﬀs’ negligence
claims. Even so, it correctly recognized that Sherwin-Williams
might still have a duty to take other actions to prevent fore-
seeable harms. (Again, a separate question is whether Sher-
win-Williams breached that duty. See Morden, 611 N.W.2d at
675–76.)
    Nor, if we assume contrary to fact that the negligence
claim should have gone to the jury, did the court err in in-
structing the jury on causation. “We review jury instructions
de novo to determine whether, taken as a whole, they cor-
rectly and completely informed the jury of the applicable
law.” Huﬀ v. Sheahan, 493 F.3d 893, 899 (7th Cir. 2007). The
court instructed the jury to decide whether the white lead car-
bonate that the plaintiﬀs ingested caused their injuries. Sher-
win-Williams contends that the proper question was whether
its negligence caused the injuries.
    The court’s jury instruction correctly stated the law. The
second element of a negligence claim under the risk-contribu-
tion theory requires the plaintiﬀ to prove “[t]hat the white
lead carbonate caused his injuries.” Thomas, 701 N.W.2d at
564. That is precisely what the court here told the jury to de-
cide. Granted, Thomas’s articulation of the causation element
of a negligence claim conﬂicts with ordinary negligence law,
which requires a causal link between a defendant’s negligence
and the plaintiﬀ’s injury. Fondell v. Lucky Stores, Inc., 270
N.W.2d 205, 209 (Wis. 1978). But the whole point of Thomas
was to modify ordinary causation principles. We cannot ac-
cept Sherwin-Williams’s suggestion that Thomas was simply
sloppy with its language. Thomas was setting forth the ele-
ments of a novel cause of action for white lead carbonate
Nos. 20-1774 et al.                                            41

plaintiﬀs. We ﬁnd it hard to believe that the court was sloppy
in carrying out that task. Indeed, we know that Thomas’s state-
ments about causation were not an accident because one of
the dissents criticized the very language about which Sher-
win-Williams now complains. Thomas, 701 N.W.2d at 591
(Prosser, J., dissenting). The district court lifted its causation
instruction straight from Thomas. That was not error.
C. Strict Liability
    Sherwin-Williams and Armstrong both challenge the strict
liability verdict. They say (1) the district court erred in ruling
that they could have a duty to warn for purposes of strict lia-
bility but not negligence; and (2) that the plaintiﬀs failed to
prove that any failure to warn caused their injuries. The dis-
trict court rejected the ﬁrst argument at summary judgment
and again when denying the defendants’ motion for judg-
ment as a matter of law. Our review is therefore de novo.
Turubchuk, 958 F.3d at 548; see also Chemetall, 320 F.3d at 719.
The court rejected the second argument when denying the de-
fendants’ motion for a new trial. We review that ruling for
abuse of discretion. Turubchuk, 958 F.3d at 548.
    Thomas set forth the elements of a prima facie case of strict
liability in white lead carbonate cases. To prevail at trial, the
plaintiﬀs had to prove:
   (1) That the white lead carbonate was defective when
   it left the possession or control of the pigment manu-
   facturers;
   (2) That it was unreasonably dangerous to the user or
   consumer;
   (3) That the defect was a cause of [the plaintiﬀs’] inju-
   ries or damages;
42                                             Nos. 20-1774 et al.

     (4) That the pigment manufacturer engaged in the
     business of producing or marketing white lead car-
     bonate or, put negatively, that this is not an isolated or
     infrequent transaction not related to the principal busi-
     ness of the pigment manufacturer; and,
     (5) That the product was one which the company ex-
     pected to reach the user or consumer without substan-
     tial change in the condition it was when sold.
Thomas, 701 N.W.2d at 564. The defendants’ challenge focuses
on the ﬁrst and third elements: defect and causation.
     1. Product Defect
    We begin with product defect. Unlike their negligence
claims, the plaintiﬀs predicated their strict liability claims on
a product defect—failure to warn. Although the district court
had ruled at summary judgment that the defendants had no
duty to warn the plaintiﬀs for purposes of the negligence
claim, it distinguished the duty to warn in the strict liability
context. Whereas negligence required a duty to warn the
plaintiﬀs, strict liability required a duty to warn the “ordinary
users and consumers” who purchased or used the defend-
ants’ products when the defendants sold them—decades be-
fore they reached the plaintiﬀs. The court found a genuine is-
sue of material fact as to whether these “ordinary users or
consumers” would have needed a warning about the dangers
of lead-based paint, given that the dangers were less widely
known in the early to mid-twentieth century.
    A properly designed and manufactured product may still
be defective if “an intended use of the product is dangerous,
but the manufacturer did not provide suﬃcient warning or
instruction.” Godoy, 768 N.W.2d at 684. Importantly, warnings
Nos. 20-1774 et al.                                           43

are necessary only when a product’s dangers are hidden. In a
negligence action, a manufacturer is not liable unless it “has
no reason to believe that those for whose use the chattel is
supplied will realize its dangerous condition.” Strasser v.
Transtech Mobile Fleet Serv., Inc., 613 N.W.2d 142, 155 (Wis.
2000) (quoting Restatement (Second) of Torts § 388 (1965)).
Similarly, in a strict liability action, “manufacturers have an
obligation to warn consumers about the hidden dangers of
their products.” Godoy, 768 N.W.2d at 685 n.15 (emphasis
added) (citing Restatement (Second) of Torts § 402A cmts. h,
i).
    The Wisconsin Supreme Court has not addressed the dif-
ference, if any, between the duty to warn for negligence and
strict liability claims, but we and other courts applying Wis-
consin law have treated them as materially identical. See, e.g.,
Flaminio, 733 F.2d at 467 (holding that the diﬀerence between
negligent and strict liability duty-to-warn claims, “if any,”
was “so small” that the district court’s failure to give separate
instructions on them was harmless); Gracyalny v. Westinghouse
Elec. Corp., 723 F.2d 1311, 1317 n.11 (7th Cir. 1983) (“[I]n duty
to warn cases, emphasis upon the nature and scope of the
warning has led to a convergence of the functional identities
of strict products liability and negligence.”); Mohr v. St. Paul
Fire & Marine Ins. Co., 674 N.W.2d 576, 590 n.10 (Wis. Ct. App.
2004) (“[T]he proof requirements for an inadequate warning
on a strict product liability claim are the same as for breach of
the duty to warn on a negligence claim.”); Tanner v. Shoupe,
596 N.W.2d 805, 811 n.3 (Wis. Ct. App. 1999); Lemmermann v.
Blue Cross Blue Shield of Wis., 713 F. Supp. 2d 791, 810 (E.D.
Wis. 2010); Nigh v. Dow Chem. Co., 634 F. Supp. 1513, 1517
(W.D. Wis. 1986).
44                                            Nos. 20-1774 et al.

    It makes sense that the duty to warn would be the same
for both types of claims because failure to warn is a type of
product defect and defect is a shared requirement for negli-
gence and strict liability claims. Godoy, 768 N.W.2d at 681 n.7;
Morden, 611 N.W.2d at 673. If there is any substantive diﬀer-
ence between negligent and strict liability failure-to-warn
claims, it likely stems from the second requirement of a strict
liability claim: that the defect render the product unreasona-
bly dangerous. See Morden, 611 N.W.2d at 673 (“In a negli-
gence action, by contrast, it is not necessary to show that the
condition of the product reached the level of unreasonable
dangerousness.”); Sharp, 595 N.W.2d at 388.
    The district court rooted its divergent approach in Thomas,
which requires, as the ﬁrst element of a strict liability claim,
that the “white lead carbonate was defective when it left the
possession or control of the pigment manufacturers.” 701 N.W.2d
at 564 (emphasis added). From this language, the court in-
ferred that the duty to warn in strict liability hinges on
whether the dangers of white lead carbonate were hidden to
the consumers of residential paint products who existed
when the defendants released their products into the market.
    We grant that, under Thomas, the absence of a warning
must have existed when the white lead carbonate left the pos-
session or control of the pigment manufacturer. Still, the ne-
cessity of a warning should depend on what the ultimate con-
sumer (i.e., the plaintiﬀs or their caregivers) knew, rather than
what consumers in general knew at the time the manufacturer
released the product into the market. See Restatement (Sec-
ond) of Torts § 402A cmt. g (“The rule stated in this Section
applies only where the product is, at the time it leaves the
seller’s hands, in a condition not contemplated by the ultimate
Nos. 20-1774 et al.                                           45

consumer, which will be unreasonably dangerous to him.”)
(emphasis added); Morden, 611 N.W.2d at 673 (“It is suﬃcient
[in strict liability] for the plaintiﬀ to show that the product
reached him in a dangerously defective condition.” (emphasis
added) (quoting Greiten, 235 N.W.2d at 684) (controlling opin-
ion of Heﬀernan, J.))). The purpose behind the requirement
that a product be defective when it leaves the hands of a man-
ufacturer is to protect the manufacturer from liability for
later-arising defects: “The seller is not liable when he delivers
the product in a safe condition, and subsequent mishandling
or other causes make it harmful by the time it is consumed.”
Restatement (Second) of Torts § 402A cmt. g. It is not to un-
tether the duty to warn from the ultimate consumer. The focus
must always remain on the ultimate consumer. See id.
    In shifting the focus away from the plaintiﬀs and toward
“ordinary consumers” living decades earlier, the district court
seems to have relied on the “consumer-contemplation” test.
See Restatement (Second) of Torts § 402A cmt. i (“The article
sold must be dangerous to an extent beyond that which
would be contemplated by the ordinary consumer who pur-
chases it, with the ordinary knowledge common to the com-
munity as to its characteristics.”); Green, 629 N.W.2d at 739.
Even if that test was relevant to duty to warn, it focuses on
ordinary consumers in the plaintiﬀs’ situation. See Insolia, 216
F.3d at 600 (“[W]hat the ordinary consumer contemplated
about the dangers of smoking should be evaluated at the time
the plaintiﬀs began smoking.”). If any “ordinary consumers”
were relevant, it was those who consumed residential paint
when the plaintiﬀs (or their caregivers) did. It was not the
broad and amorphous category of individuals who consumed
residential paint at any time when the defendants were
46                                            Nos. 20-1774 et al.

manufacturing white lead carbonate—i.e., during large
chunks of the twentieth century.
    For these reasons, the court legally erred in ﬁnding that
the defendants had a duty to warn for purposes of strict lia-
bility after ruling at summary judgment that they had no duty
to warn the plaintiﬀs on their negligence claims. The plaintiﬀs
have not appealed the court’s ruling that the defendants had
no duty to warn for purposes of the negligence claims. This
ruling compels judgment as a matter of law for Sherwin-Wil-
liams and Armstrong on the strict liability claims.
     2. Causation
    We turn next to causation. Before trial, the court ruled that
each plaintiﬀ had to prove “that the presence of inadequately-
warned-about [white lead carbonate] on the market during
the existence of the residence where the plaintiﬀ ingested
[white lead carbonate] was a substantial factor in causing the
plaintiﬀ’s injury.” It acknowledged that proving such a “ten-
uous connection” would be “a tall order.” But it rejected the
defendants’ argument that the plaintiﬀs had to present expert
testimony to prove causation; in the court’s view, inferring
causation did “not require specialized technical, scientiﬁc or
medical knowledge,” but could “be made on the basis of com-
mon understandings of human behavior.”
    Consistent with this ruling, the court instructed the jury to
decide whether the plaintiﬀs had proven that “the allegedly
defective warnings were a cause of the plaintiﬀs’ injuries.” To
answer “yes,” the jury had to ﬁnd that “the sale of white lead
carbonate with inadequate warnings was a substantial factor
in causing the plaintiﬀs’ injury.” For example, the jury could
“consider whether the persons responsible for selecting and
Nos. 20-1774 et al.                                           47

applying paint in the plaintiﬀs’ homes throughout the build-
ings’ existence would have heeded warnings about the risk of
childhood lead exposure if such warnings had been issued.”
    It turns out that this causation standard was indeed a “tall
order” for the plaintiﬀs. It is essentially undisputed that the
plaintiﬀs presented no evidence at trial that the supposed de-
fect—failure to warn—caused their injuries. In closing argu-
ments, the plaintiﬀs appealed to the jurors’ “common sense,”
arguing that “moms and dads back in the ‘20s and ‘30s and
‘40s and ‘50s” would never have purchased paint containing
white lead carbonate if they had known the risks it posed to
their children. But the only evidence they relied on was testi-
mony that consumers in the ﬁrst half of the twentieth century
were unaware of the risks of white lead carbonate. They in-
troduced no evidence of whether adequate warnings would
have altered consumer behavior—much less prevented their
injuries.
   The defendants brought this failure of proof to the district
court’s attention in their motions for a new trial. The plaintiﬀs
did not respond to these arguments for a new trial. Even so,
the court denied the defendants’ motions, and in doing so it
departed from its earlier theory of causation. Implicitly ac-
knowledging the plaintiﬀ’s total failure of proof on this ele-
ment, the court explained that the plaintiﬀs did not have to
show that “appropriate warnings would have changed con-
sumer behavior;” rather, they only had to show “that the dan-
gers posed by [white lead carbonate] were outside the con-
templation of the ordinary consumer,” at which point it be-
came the defendants’ burden to prove that their warnings
“were suﬃcient to render safe [the] otherwise dangerously
48                                            Nos. 20-1774 et al.

defective product.” On appeal, the plaintiﬀs have again failed
to respond to the defendants’ causation arguments.
    The court was correct the ﬁrst time: the plaintiﬀs had to
prove that the product defect—i.e., failure to warn—caused
their injuries. See Thomas, 701 N.W.2d at 564 (requiring proof
“[t]hat the defect was a cause of Thomas’s injuries or dam-
ages”); accord Godoy, 768 N.W.2d at 681 n.7. The court’s post-
trial ruling improperly collapsed the second and third ele-
ments of a strict liability claim and shifted the burden to the
defendants. In Green, the Wisconsin Supreme Court advised
that a defendant could show that its product was not “unrea-
sonably dangerous” by proving “that the product include[d]
a warning or directions that eﬀectively alert[ed] the ordinary
consumer” to the product’s dangers. 629 N.W.2d at 754. This
inquiry, which goes to the second element of a strict liability
claim (unreasonable danger), is separate from the third ele-
ment (causation). See Thomas, 701 N.W.2d at 564; Godoy, 768
N.W.2d at 681 n.7. A plaintiﬀ must always prove causation.
See Thomas, 701 N.W.2d at 564.
   Because the plaintiﬀs do not dispute that they failed to
present evidence of causation at trial, we need not address
what type of evidence might suﬃce to prove causation. More-
over, because the defendants do not directly challenge the
court’s pretrial ruling on causation or its jury instructions, we
need not address whether the court correctly stated the rele-
vant legal principles (before departing from them post-trial).
    Normally, the plaintiﬀs’ failure to prove causation would
require at least a new trial. In this case, however, any such
relief would be redundant because Sherwin-Williams and
Armstrong are already entitled to judgment as a matter of law
Nos. 20-1774 et al.                                           49

on the strict liability claims, given the absence of a product
defect.
                               ***
    We reject the defendants’ other attacks on the strict liabil-
ity verdict. The defendants argue ﬁrst that the “ordinary con-
sumers” of white lead carbonate were master painters and
paint manufacturers, who required no warning as to the dan-
gers of white lead carbonate. The defendants’ argument ap-
pears to rest on one of two mistaken premises: (1) that prod-
ucts liability claims require “privity of contract,” or (2) that
component parts suppliers cannot be liable to the ultimate
consumer. The Wisconsin Supreme Court has ﬂatly rejected
both arguments. Godoy, 768 N.W.2d at 681 (noting that the
Second Restatement discarded the privity-of-contract re-
quirement); id. at 688 (“When component manufacturers in-
troduce defective components into the stream of commerce,
they may be held liable for resulting injuries under the partic-
ular circumstances of the case.”).
    Moving to the ﬁfth element of the strict liability claim, the
defendants argue that their white lead carbonate could not
have reached the plaintiﬀs without undergoing a “substantial
change in condition”—i.e., integration into paint, application
of paint to the plaintiﬀs’ homes, and a lack of maintenance
allowing the paint to deteriorate and become ingestible.
Thomas, 701 N.W.2d at 564. “[T]o succeed under the substan-
tial change defense, the change must be both substantial and
material.” Godoy, 768 N.W.2d at 687. “The purpose of this re-
quirement is to protect a manufacturer from liability when the
dangerously defective aspect of the product was altered or in-
troduced after the product left the manufacturer’s control.” Id.
This is a “fact-intensive inquiry.” Id.
50                                            Nos. 20-1774 et al.

    We agree with the district court that any changes to the
defendants’ white lead carbonate were “not material, since
the [white lead carbonate] was already toxic and in powder
form before it underwent these changes.” White lead car-
bonate is the singular source of lead poisoning in paint that
contains it. As Thomas said, “the inherent dangerousness of
the white lead carbonate pigment existed the moment the Pig-
ment Manufacturers created it.” 701 N.W.2d at 563. If any-
thing, mixing it into paint “diluted the white lead carbonate’s
toxicity.” Id. The deterioration of the paint may have helped
facilitate the plaintiﬀs’ ingestion of the white lead carbonate,
but it did not introduce or alter its toxicity. The jury was on
ﬁrm ground in ﬁnding no substantial change in condition.
D. Other Issues
    Sherwin-Williams and Armstrong raise several other chal-
lenges. Ordinarily we would avoid reaching these issues if
possible. We are mindful, however, that there are a slew of
similar cases pending at the district court and moving toward
trial. As such, we will address some of these other issues in
hopes of providing clarity for future trials.
     1. Expert Testimony
    Sherwin-Williams and Armstrong claim that the plaintiﬀs
failed to prove the existence, cause, and extent of their injuries
through admissible evidence. They challenge the district
court’s admission of Dr. Trope’s and Dr. Besunder’s testi-
mony on these issues. “We review de novo whether a district
court properly followed the framework for determining the
admissibility of expert testimony.” Schultz v. Akzo Nobel
Paints, LLC, 721 F.3d 426, 430–31 (7th Cir. 2013); see also Fed.
R. Evid. 702; Daubert v. Merrell Dow Pharm., Inc., 509 U.S. 579
Nos. 20-1774 et al.                                              51

(1993). If it did, “we review its decision to admit or exclude
expert testimony only for an abuse of discretion.” Schultz, 721
F.3d at 431. We review de novo the court’s denial of judgment
as a matter of law on this ground. Turubchuk, 958 F.3d at 548.
   Federal Rule of Evidence 702 permits a qualiﬁed expert
witness to oﬀer an opinion if:
   (a) the expert’s scientiﬁc, technical, or other specialized
   knowledge will help the trier of fact to understand the
   evidence or to determine a fact in issue;
   (b) the testimony is based on suﬃcient facts or data;
   (c) the testimony is the product of reliable principles
   and methods; and
   (d) the expert has reliably applied the principles and
   methods to the facts of the case.
Courts can examine the reliability of an expert’s principles
and methods by looking at factors such as “(1) whether the
scientiﬁc theory or technique can be (and has been) tested; (2)
whether the theory or technique has been subjected to peer
review and publication; (3) whether a particular technique
has a known potential rate of error; and (4) whether the theory
or technique is generally accepted in the relevant scientiﬁc
community.” Schultz, 721 F.3d at 431 (citing Daubert, 509 U.S.
at 593–94). This list is not exhaustive. Daubert, 509 U.S. at 593.
   Although Rule 702 “places the judge in the role of gate-
keeper for expert testimony, the key to the gate is not the ul-
timate correctness of the expert’s conclusions” but rather “the
soundness and care with which the expert arrived at her opin-
ion.” Schultz, 721 F.3d at 431. “So long as the principles and
methodology reﬂect reliable scientiﬁc practice, ‘[v]igorous
52                                            Nos. 20-1774 et al.

cross-examination, presentation of contrary evidence, and
careful instruction on the burden of proof are the traditional
and appropriate means of attacking shaky but admissible ev-
idence.’” Id. (quoting Daubert, 509 U.S. at 596).
    We begin with Dr. Trope. The defendants claim that her
method for determining that each of the plaintiﬀs had brain
damage—administering a neuropsychological evaluation—
was unreliable, primarily because it failed to exclude alterna-
tive causes. As Dr. Trope testiﬁed, however, she did not need
to exclude alternative causes to testify to the fact of brain dam-
age. And the defendants’ other attacks on the reliability of
neuropsychological evaluations are unpersuasive. Dr. Trope
and Dr. Besunder both testiﬁed that neuropsychological eval-
uations are the standard, well-accepted method for ascertain-
ing whether an individual has brain damage. (The defend-
ants’ own expert relied on a similar methodology to testify
that the plaintiﬀs did not have brain damage.) Many of the
defendants’ arguments wrongly equate neuropsychological
evaluations with basic aptitude tests. As Dr. Trope explained,
a neuropsychological evaluation tests how diﬀerent parts of
the brain function compared to one other—not how they
function on the whole. Large discrepancies indicate brain
damage, according to both Dr. Trope and Dr. Besunder. We
see no abuse of discretion in the court’s decision to allow Dr.
Trope to testify that the plaintiﬀs had brain damage. The de-
fendants were free to cross-examine Dr. Trope about any
weaknesses in her methodology. Schultz, 721 F.3d at 431.
    Dr. Trope’s testimony that lead poisoning caused the
plaintiﬀs’ brain damage presents a more diﬃcult question be-
cause the plaintiﬀs did not oﬀer her to prove causation; she
testiﬁed to it only on cross-examination, over the plaintiﬀs’
Nos. 20-1774 et al.                                               53

objections. Moreover, the defendants suggest that Dr. Trope,
who is not a medical doctor, was unqualiﬁed to diagnose the
plaintiﬀs’ brain injuries.
    We need not resolve this issue. Any error in the admission
of Dr. Trope’s causation testimony was harmless because the
court was within its discretion to admit Dr. Besunder’s causa-
tion testimony. Dr. Besunder testiﬁed that childhood lead poi-
soning was the source of the plaintiﬀs’ injuries. He reached
that conclusion by comparing their brain functioning—as
shown in their neuropsychological evaluations—to docu-
mented patterns of brain functioning in other individuals
who had suﬀered childhood lead poisoning. He testiﬁed that
this type of comparison is a well-accepted method of ascer-
taining the cause of brain damage, and that he uses it in his
own practice. He also testiﬁed that he reviewed the plaintiﬀs’
medical records to determine whether there were potential al-
ternative causes of their brain damage. See Schultz, 721 F.3d at
434 (noting that “a reliable expert should consider alternative
causes” but need not “rule out every alternative cause”); My-
ers v. Illinois Cent. R.R. Co., 629 F.3d 639, 644–45 (7th Cir. 2010);
see also Thomas, 701 N.W.2d at 563 (reasoning that the poten-
tial for alternative causes of brain damage was an issue for the
jury). To the extent that Dr. Besunder could not rule out every
alternative cause, the defendants could—and did—try to
bring that out through cross-examination. Moreover, the
plaintiﬀs had to prove that lead poisoning was a substantial
factor leading to their lead poisoning—not the sole cause.
Schultz, 721 F.3d at 433 (applying Wisconsin law).
    Dr. Besunder’s testimony about the extent of the plaintiﬀs’
injuries is a diﬀerent story. Dr. Besunder’s IQ-loss testimony
was a critical component of the plaintiﬀs’ cases because it
54                                            Nos. 20-1774 et al.

attempted to measure the extent of their injuries—and, thus,
their damages. Yet the district court performed essentially no
analysis of whether Dr. Besunder’s methodology—using gen-
eral epidemiological studies to quantify the plaintiﬀs’ indi-
vidual IQ losses—was reliable. The defendants argued, with-
out apparent contradiction, that Dr. Besunder’s methodology
was unprecedented. They also argued that it was unreliable
because Dr. Besunder did not personally evaluate the plain-
tiﬀs, nor did he have any evidence of their baseline IQs—even
though the plaintiﬀs’ other experts testiﬁed that they could
not quantify the plaintiﬀs’ IQ losses without knowing the
plaintiﬀs’ parents’ IQ scores. The court dismissed these objec-
tions as issues for the jury. But trial judges are the “gate-
keeper[s] for expert testimony.” Schultz, 721 F.3d at 431. Be-
fore allowing an expert to testify before the jury, the judge
must ensure that the expert’s “principles and methodology
reﬂect reliable scientiﬁc practice.” Id. The district court failed
to perform its gatekeeping function and ensure that Dr. Be-
sunder’s IQ-loss testimony rested on a reliable methodology,
so the court abused its discretion in admitting it.
    The district court’s admission of Dr. Besunder’s IQ-loss
testimony requires a new trial because there is “a signiﬁcant
chance” that the jury’s identical $2 million damages awards
rested on Dr. Besunder’s testimony about the extent of the
plaintiﬀs’ injuries. Smith v. Hunt, 707 F.3d 803, 808 (7th Cir.
2013). (After all, the court remitted Burton’s damages award
to $800,000 post-trial because Dr. Besunder admitted that, of
the 10 IQ points that Burton lost due to lead poisoning, he lost
six of them before he moved to the home that he focused on
at trial.) As a practical matter, this relief only impacts Arm-
strong’s liability on the negligence claim. For reasons dis-
cussed above, Sherwin-Williams is entitled to judgment as a
Nos. 20-1774 et al.                                              55

matter of law on both claims and Armstrong is entitled to
judgment as a matter of law on the strict liability claim.
   2. Bifurcation
    Next, Sherwin-Williams and Armstrong contend that the
district court erred in bifurcating the trial into a liability phase
and an apportionment phase and then excluding evidence
about National Lead—the dominant producer of white lead
carbonate pigment in the Milwaukee market—from the liabil-
ity phase. They claim that the district court’s rulings ham-
pered their defenses and gave the jury the mistaken impres-
sion that at least one of the defendants on the verdict form
must have been the responsible party.
   We review the court’s decision to bifurcate the trial for
abuse of discretion. Volkman v. Ryker, 736 F.3d 1084, 1089 (7th
Cir. 2013). We use the same standard to review whether the
court erred in excluding evidence of National Lead or deny-
ing a new trial on this basis. Turubchuk, 958 F.3d at 548–49.
    We see no abuse of discretion. Absent some clear preju-
dice, we will not fault the court for attempting to inject some
semblance of order into this complex case—especially given
district courts’ “inherent authority to manage the course of
trials.” Luce v. United States, 469 U.S. 38, 41 n.4 (1984). The
court’s structure of the trial harmonized with Collins’s design
to (1) create “a pool of defendants which can reasonably be
assumed ‘could have caused the plaintiﬀ’s injuries’” and then
(2) apportion liability among those “defendants who cannot
exculpate themselves” through comparative negligence.
Thomas, 701 N.W.2d at 565 (quoting Collins, 342 N.W.2d at 52).
In this respect we ﬁnd it relevant that Collins expressly de-
clined to adopt a “market-share” theory of liability, instead
56                                            Nos. 20-1774 et al.

holding that market share was “a relevant factor in apportion-
ing liability among defendants.” Collins, 342 N.W.2d at 48–49.
Under Collins, the defendants had every right to point the ﬁn-
ger at National Lead during the apportionment phase of trial.
They chose instead to settle and assign National Lead 12.5%
of the damages. Their informed decision to settle prevents
them from now complaining about not having been able to
introduce evidence of National Lead’s market domination.
    To the extent that evidence of National Lead had any rel-
evance in the liability phase—which is far from clear—the dis-
trict court did not abuse its discretion in concluding that the
likelihood of confusion and prejudice substantially out-
weighed any such probative value. The defendants strain to
connect evidence of National Lead to their liability defenses.
As the district court pointed out, it is hard to see how evidence
of National Lead’s market domination had any bearing on
whether another manufacturers’ white lead carbonate could
have reached the plaintiﬀs, which is the liability inquiry un-
der Collins. Id. at 52. Meanwhile, it would have been all too
easy for the defendants to point the ﬁnger at National Lead
and rely on the unstated implication that National Lead was
probably the responsible party. Such a maneuver would have
been inconsistent with the risk-contribution theory that Col-
lins and Thomas adopted. Finally, there is no basis for the de-
fendants’ assertion that the jury was led to believe that one of
the defendants who went to trial must have produced the
white lead carbonate that injured the plaintiﬀs. In fact, the
court dismissed American Cyanamid at the close of evidence
and then instructed the jury not to consider any claims against
American Cyanamid and not to speculate as to why it was no
longer a defendant.
Nos. 20-1774 et al.                                              57

   3. Public Policy
    Forging along, Sherwin-Williams and Armstrong contend
that Wisconsin’s judicial public policy factors require over-
turning the jury verdicts against them. They claim that Wis-
consin public policy does not tolerate holding them liable for
injuries that they likely did not cause, which occurred decades
after they stopped making white lead carbonate. They add
that their liability is vastly out of proportion to the culpability
of producing or marketing white lead carbonate at a time
when it was widely used in residential paints.
   We review de novo the court’s denial of judgment not-
withstanding the verdict. Turubchuk, 958 F.3d at 548; see also
Fandrey, 680 N.W.2d at 350 (whether the public policy factors
preclude liability is a question of law).
    Wisconsin’s public policy factors are judicial policy con-
siderations that function like a proximate cause analysis. See
Fandrey, 680 N.W.2d at 350–51, 351 n.7. “[W]hen a court pre-
cludes liability based on public policy factors, it is essentially
concluding that despite the existence of cause-in-fact, the
cause of the plaintiﬀ’s injuries is not legally suﬃcient to allow
recovery.” Id. at 353. Overriding a jury verdict based on public
policy considerations is “infrequent” and requires “unusual
and extreme considerations.” Roehl Transp., Inc. v. Liberty Mut.
Ins. Co., 784 N.W.2d 542, 568 (Wis. 2010) (internal quotation
marks and citations omitted). The six public policy factors are:
(1) is the injury too remote from the defendant’s conduct? (2)
is the plaintiﬀ’s injury disproportionate to the defendant’s
culpability? (3) is it too extraordinary, in hindsight, that liabil-
ity would attach here? (4) is the potential liability too burden-
some for the defendant? (5) will imposing liability open the
way to fraudulent claims? and (6) is there a sensible or just
58                                            Nos. 20-1774 et al.

stopping point to the theory of liability? See Fandrey, 680
N.W.2d at 348 n.1.
    If the defendants’ public policy arguments look familiar, it
is because they closely resemble the dissents in Thomas. At
their core, the defendants’ public policy arguments are argu-
ments against Thomas itself. One of the dissents in Thomas sim-
ilarly argued that the public policy factors precluded liability.
701 N.W.2d at 596–97 (Prosser, J., dissenting). The majority
did not directly engage with that argument, id. at 565 n.54, but
its reasoning for extending the risk-contribution theory was
anchored in countervailing policy considerations, and many
of its statements were directly responsive to the dissent’s pub-
lic policy arguments. See, e.g., id. at 562 (“[T]he Pigment Man-
ufacturers’ argument must be put into perspective: they are
essentially arguing that their negligent conduct should be ex-
cused because they got away with it for too long.”); see also
Collins, 342 N.W.2d at 52 (accepting the possibility that inno-
cent defendants could be found liable as “the price the de-
fendants, and perhaps ultimately society, must pay to provide
the plaintiﬀ an adequate remedy under the law”). We cannot
accept that the Wisconsin Supreme Court would create a
cause of action based on judicial policy considerations only to
later hold that the same cause of action would violate judicial
policy considerations. The public policy factors operate as a
check on liability in rare cases. We will not hold, in essence,
that they categorically preclude liability under Thomas.
    Nor does Wis. Stat. § 895.046 aﬀect our conclusion. Wis-
consin’s public policy factors are judicial policy considera-
tions whose role stands in “stark contrast” to the legislature’s
declarations of public policy. Fandrey, 680 N.W.2d at 354. That
Nos. 20-1774 et al.                                           59

is why the public policy factors may preclude liability even
where a statute authorizes it. Id. at 350.
   4. Successor Liability
    Armstrong also challenges the district court’s ruling at
summary judgment that Armstrong was MacGregor’s succes-
sor-in-interest. Armstrong contends that the relevant asset
purchase agreement is ambiguous as to whether Armstrong’s
admitted predecessor-in-interest assumed MacGregor’s fu-
ture legal liabilities, such as damages arising from the plain-
tiﬀs’ lawsuits. And because the contract is ambiguous, Arm-
strong says its meaning was an issue for the jury. Our review
is de novo. Turubchuk, 958 F.3d at 548; see also Chemetall, 320
F.3d at 719.
    Neither party raised choice of law issues below, so we ap-
ply the law of the forum—Wisconsin. Camp v. TNT Logistics
Corp., 553 F.3d 502, 505 (7th Cir. 2009) (citing Wood v. Mid-Val-
ley Inc., 942 F.2d 425, 426 (7th Cir. 1991)). Under Wisconsin
law, “[w]hen the terms of a contract are clear and unambigu-
ous, we construe the contract’s language according to its lit-
eral meaning.” Ash Park, LLC v. Alexander & Bishop, Ltd., 866
N.W.2d 679, 685 (Wis. 2015). “When the terms of a contract
are ambiguous, however, evidence extrinsic to the contract it-
self may be used to determine the parties’ intent, and any re-
maining ambiguities will be construed against the drafter.” Id.
“A contract provision is ambiguous if it is fairly susceptible of
more than one construction.” Id. (quoting Mgmt. Computer
Servs., Inc. v. Hawkins, Ash, Baptie & Co., 557 N.W.2d 67, 75
(Wis. 1996)).
   In relevant part, the asset purchase agreement provides
that Armstrong’s predecessor will assume “the liabilities and
60                                             Nos. 20-1774 et al.

obligations” of the sellers, including “[o]bligations with re-
spect to litigation and claims against Sellers other than litiga-
tion and claims involving or arising out of liabilities and obli-
gations expressly not assumed.” The agreement also includes
a catchall providing that, “[e]xcept for the obligations and li-
abilities” excluded elsewhere, Armstrong’s predecessor will
“assume all other obligations of sellers, whether accrued, con-
tingent or future, based on, related to or arising out of events
or occurrences prior to the closing, whether known or un-
known and regardless of when arising or asserted.”
    Armstrong maintains that the terms “obligations” and “li-
abilities” are ambiguous, such that its predecessor’s assump-
tion of “obligations with respect to litigation and claims” does
not necessarily include all future legal “liabilities,” including
damages arising from a lawsuit based on unforeseen events.
   We disagree. To be sure, the contract is not a model of clear
drafting, and the terms “obligations” and “liabilities” are not
used consistently throughout. But, at least in the provisions
quoted above, “obligations” must encompass “liabilities” be-
cause “obligations” is used as an umbrella term from which
other “liabilities and obligations” are excluded. Moreover, the
plain terms of the exceptionally broad catchall easily encom-
pass the damages liability in this case (and Armstrong cannot
point to any other provision that speciﬁcally excludes it).
    Even if the contract were ambiguous, moreover, Arm-
strong has not demonstrated a genuine issue of material fact
as to its meaning. When courts are stumped about the mean-
ing of contracts, they do not simply hand the ambiguous con-
tracts to juries. Rather, if a court decides that a contract is am-
biguous, the parties may introduce extrinsic evidence of in-
tent, and the jury resolves the fact question of what the parties
Nos. 20-1774 et al.                                             61

intended, using on the extrinsic evidence. See Town Bank v.
City Real Estate Dev., LLC, 793 N.W.2d 476, 483 (Wis. 2010).
Armstrong does not represent that it has any extrinsic evi-
dence of the parties’ intent, so it has not demonstrated a jury
issue.
   5. First Amendment
    Finally, Sherwin-Williams argues that the district court vi-
olated its First Amendment rights by allowing the plaintiﬀs to
introduce evidence of its product advertisements and associ-
ations with industry groups. The district court deemed this
evidence relevant to certain aspects of the plaintiﬀs’ claims,
including Sherwin-Williams’s knowledge of the hazards of
lead-based paint and its presence in the Milwaukee market.
And because Sherwin-Williams’s liability rested on its pro-
duction and sale of white lead carbonate—rather than its pro-
tected activities—the court saw no constitutional problem
with admitting the evidence. We review the court’s First
Amendment analysis de novo, while reviewing its decisions
to admit the evidence and deny a new trial for abuse of dis-
cretion. See Turubchuk, 958 F.3d at 548.
    Sherwin-Williams is profoundly mistaken about the role
of the First Amendment in evidentiary rulings. The First
Amendment does not bar the admission of any and all evi-
dence that falls within its protection. Just last month, we held
that such a view of the First Amendment “utterly misunder-
stands the burdens of production and persuasion in litiga-
tion.” Gonzales v. Madigan, 990 F.3d 561, 564 (7th Cir. 2021).
The First Amendment steps in only when the protected activ-
ity itself is the basis for liability. See NAACP v. Claiborne Hard-
ware Co., 458 U.S. 886, 918–19 (1982) (“The First Amendment
… restricts the ability of the State to impose liability on an
62                                            Nos. 20-1774 et al.

individual solely because of his association with another.”)
(emphasis added). Here, the plaintiﬀs introduced evidence of
Sherwin-Williams’s advertisements and associations to prove
elements of their claims. They did not ask the jury to ﬁnd
Sherwin-Williams liable for engaging in these protected activ-
ities. Cf. Snyder v. Phelps, 562 U.S. 443, 461 (2011) (overturning
a jury verdict ﬁnding the defendants liable for picketing on
matters of public concern). Thus, the district court did not
abuse its discretion in admitting this evidence.
                               ***
   We have considered the defendants’ remaining arguments
and determined that none merits discussion.
                        III. Conclusion
    For these reasons, we REVERSE the judgments and
REMAND for further proceedings consistent with our opin-
ion and the following instructions. Sherwin-Williams is enti-
tled to judgment as a matter of law on both claims that went
to trial. Armstrong is entitled to judgment as a matter of law
on the strict liability claims and a new trial on the negligence
claims. DuPont is entitled to a new trial on both claims.
    We close by commending Judge Adelman for his thought-
ful dedication to these complex cases. Circuit Rule 36 supplies
a default rule of reassignment when cases are remanded for
new trials. Given Judge Adelman’s enormous investments of
time and eﬀort in these cases, we believe that the interests of
judicial eﬃciency favor retaining Judge Adelman as the trial
judge in these cases. We therefore direct that Rule 36 shall not
apply on remand. See Cir. R. 36 (providing for reassignment
“unless the remand order directs … that the same judge retry
the case”).