(Slip Opinion) OCTOBER TERM, 2022 1 

Syllabus 

NOTE: Where it is feasible, a syllabus (headnote) will be released, as is 

being done in connection with this case, at the time the opinion is issued. 

The syllabus constitutes no part of the opinion of the Court but has been 

prepared by the Reporter of Decisions for the convenience of the reader. 

See United States v. Detroit Timber & Lumber Co., 200 U. S. 321, 337. 

SUPREME COURT OF THE UNITED STATES 

Syllabus 

GLACIER NORTHWEST, INC., DBA CALPORTLAND v. 

INTERNATIONAL BROTHERHOOD OF TEAMSTERS 

LOCAL UNION NO. 174 

CERTIORARI TO THE SUPREME COURT OF WASHINGTON 

No. 21–1449. Argued January 10, 2023—Decided June 1, 2023 

Glacier Northwest delivers concrete to customers in Washington State 

using ready-mix trucks with rotating drums that prevent the concrete 

from hardening during transit. Concrete is highly perishable, and 

even concrete in a rotating drum will eventually harden, causing significant damage to the vehicle. Glacier’s truck drivers are members of 

the International Brotherhood of Teamsters Local Union No. 174. After a collective-bargaining agreement between Glacier and the Union

expired, the Union called for a work stoppage on a morning it knew the 

company was in the midst of mixing substantial amounts of concrete, 

loading batches into ready-mix trucks, and making deliveries. The 

Union directed drivers to ignore Glacier’s instructions to finish deliveries in progress. At least 16 drivers who had already set out for deliveries returned with fully loaded trucks. By initiating emergency 

maneuvers to offload the concrete, Glacier prevented significant damage to its trucks, but all the concrete mixed that day hardened and 

became useless. 

Glacier sued the Union for damages in state court, claiming that the 

Union intentionally destroyed the company’s concrete and that this 

conduct amounted to common-law conversion and trespass to chattels. 

The Union moved to dismiss Glacier’s tort claims on the ground that

the National Labor Relations Act (NLRA) preempted them. While a 

federal law generally preempts state law when the two conflict, the 

NLRA preempts state law even when the two only arguably conflict. 

San Diego Building Trades Council v. Garmon, 359 U. S. 236, 245. In 

the Union’s view, the NLRA—which protects employees’ rights “to selforganization, to form, join, or assist labor organizations, . . . and to en-
 

 

 

 

2 GLACIER NORTHWEST, INC. v. TEAMSTERS 

Syllabus 

gage in other concerted activities for the purpose of collective bargaining or other mutual aid or protection,” 29 U. S. C. §157—at least arguably protected the drivers’ conduct, so the State lacked the power to

hold the Union accountable for any of the strike’s consequences. The 

Washington Supreme Court agreed with the Union, reasoning that 

“the NLRA preempts Glacier’s tort claims related to the loss of its concrete product because that loss was incidental to a strike arguably protected by federal law.” 

Held: The NLRA did not preempt Glacier’s tort claims alleging that the 

Union intentionally destroyed the company’s property during a labor 

dispute. Pp. 6–12.

(a) The parties agree that the NLRA protects the right to strike but 

that this right is not absolute. The National Labor Relations Board 

has long taken the position—which the parties accept—that the NLRA

does not shield strikers who fail to take “reasonable precautions” to 

protect their employer’s property from foreseeable, aggravated, and

imminent danger due to the sudden cessation of work. Bethany Medical Center, 328 N. L. R. B. 1094. Given this undisputed limitation on 

the right to strike, the Court concludes that the Union has not met its

burden as the party asserting preemption to demonstrate that the

NLRA arguably protects the drivers’ conduct. Longshoremen v. Davis, 

476 U. S. 380, 395. Accepting the complaint’s allegations as true, the 

Union did not take reasonable precautions to protect Glacier’s property

from imminent danger resulting from the drivers’ sudden cessation of

work. The Union knew that concrete is highly perishable, that it can 

last for only a limited time in a delivery truck’s rotating drum, and 

that concrete left to harden in a truck’s drum causes significant damage to the truck. The Union nevertheless coordinated with truck drivers to initiate the strike when Glacier was in the midst of batching 

large quantities of concrete and delivering it to customers. The resulting risk of harm to Glacier’s equipment and destruction of its concrete

were both foreseeable and serious. The Union thus failed to “take reasonable precautions to protect” against this foreseeable and imminent

danger. Bethany Medical Center, 328 N. L. R. B., at 1094. Indeed, far 

from taking reasonable precautions, the Union executed the strike in

a manner designed to achieve those results. Because such conduct is 

not arguably protected by the NLRA, the state court erred in dismissing Glacier’s tort claims as preempted. Pp. 6–8.

(b) The Union’s efforts to resist the conclusion that the NLRA does 

not arguably protect its conduct are unavailing. First, the Union emphasizes that the NLRA’s protection of the right to strike should be 

interpreted generously. But the protected right to strike is not absolute, thus the Court must analyze whether the strike exceeded the limits of conduct protected by the statute. 
 

 

 

 

Cite as: 598 U. S. ____ (2023) 3 

Syllabus 

Second, the Union argues that workers do not forfeit the NLRA’s 

protections simply by commencing a work stoppage when the loss of 

perishable products is foreseeable, but this case involves much more 

than that. Given the lifespan of wet concrete, Glacier could not batch

it until a truck was ready to take it. By reporting for duty and pretending as if they would deliver the concrete, the drivers prompted the

creation of the perishable product. Then, they waited to walk off the 

job until the concrete was mixed and poured in the trucks. In so doing, 

they not only destroyed the concrete but also put Glacier’s trucks in 

harm’s way. 

Third, the Court acknowledges that the Union’s decision to initiate

the strike during the workday and failure to give Glacier specific notice

do not themselves render the Union’s conduct unprotected. Still, these 

actions are relevant considerations in evaluating whether strikers took

reasonable precautions, whether harm to property was imminent, and 

whether that danger was foreseeable. See International Protective 

Services, Inc., 339 N. L. R. B. 701, 702–703. Here, the Union’s choice 

to call a strike after its drivers had loaded a large amount of wet concrete into Glacier’s delivery trucks strongly suggests that it failed to

take reasonable precautions to avoid foreseeable, aggravated, and imminent harm to Glacier’s property.

Finally, while the Union maintains that the drivers took some steps 

to protect the trucks, the Union concedes that the NLRA does not arguably protect its actions if those actions posed a material risk of harm

to the trucks. Given that Glacier alleges that the Union took affirmative steps to endanger Glacier’s property rather than reasonable precautions to mitigate that risk, the NLRA does not arguably protect the 

Union’s conduct. Pp. 8–12. 

198 Wash. 2d 768, 500 P. 3d 119, reversed and remanded.

 BARRETT, J., delivered the opinion of the Court, in which ROBERTS, 

C. J., and SOTOMAYOR, KAGAN, and KAVANAUGH, JJ., joined. THOMAS, J., 

filed an opinion concurring in the judgment, in which GORSUCH, J., 

joined. ALITO, J., filed an opinion concurring in the judgment, in which 

THOMAS and GORSUCH, JJ., joined. JACKSON, J., filed a dissenting opinion. 
 

_________________ 

_________________ 

Cite as: 598 U. S. ____ (2023) 1 

Opinion of the Court 

NOTICE: This opinion is subject to formal revision before publication in the 

United States Reports. Readers are requested to notify the Reporter of 

Decisions, Supreme Court of the United States, Washington, D. C. 20543, 

pio@supremecourt.gov, of any typographical or other formal errors. 

SUPREME COURT OF THE UNITED STATES 

No. 21–1449 

GLACIER NORTHWEST, INC., DBA CALPORTLAND, 

PETITIONER v. INTERNATIONAL BROTHERHOOD 

OF TEAMSTERS LOCAL UNION NO. 174 

ON WRIT OF CERTIORARI TO THE SUPREME COURT OF 

WASHINGTON 

[June 1, 2023]

 JUSTICE BARRETT delivered the opinion of the Court. 

Glacier Northwest, a concrete company, depends on its

truck drivers to deliver concrete to customers in a timely 

manner. But when relations between Glacier and its drivers soured, the drivers went on strike. Their labor union 

allegedly designed the strike with the intent to sabotage 

Glacier’s property. Although Glacier managed to avoid 

damage to its delivery trucks by deploying emergency maneuvers, the concrete that it had already produced that day 

went to waste. Glacier sued the union in state court for destroying its property. But the company did not get very far:

The state court dismissed Glacier’s tort claims on the 

ground that they were preempted by the National Labor 

Relations Act. We reverse. 

I 

A 

Enacted in 1935, the National Labor Relations Act 

(NLRA) “encourag[es] the practice and procedure of collective bargaining” between labor and management to resolve

“industrial disputes arising out of differences as to wages, 
 

 

2 GLACIER NORTHWEST, INC. v. TEAMSTERS 

Opinion of the Court 

hours, or other working conditions.” 49 Stat. 449, 29 

U. S. C. §151. Section 7 of the NLRA protects employees’ 

rights “to self-organization, to form, join, or assist labor organizations, to bargain collectively through representatives

of their own choosing, and to engage in other concerted activities for the purpose of collective bargaining or other mutual aid or protection.” §157. Section 8, in turn, prohibits

employers and unions from engaging in certain “unfair labor practice[s],” such as interfering with employees’ exercise of their §7 rights. §§158(a), (b). 

To enforce the NLRA, Congress created the National Labor Relations Board. The Board is authorized “to prevent

any person from engaging in any unfair labor practice” that

“affect[s] commerce.” §160(a). Its authority kicks in when 

a person files a charge with the agency alleging that an unfair labor practice is afoot. 29 CFR §101.2 (2021). Agency

staff investigate the charge, and if it “appears to have 

merit,” the agency issues a complaint against the offending 

party. §§101.4, 101.8. After taking evidence and conducting a hearing, the Board makes the final call. 29 U. S. C. 

§§160(b), (c); see also 29 CFR §§101.10–101.12. If it determines that a party has engaged in an unfair labor practice, 

the Board orders it to “cease and desist” from that practice. 

29 U. S. C. §160(c). The Board may seek enforcement of its

order in a federal court of appeals. §160(e). And a party

aggrieved by the order may ask the court to set it aside. 

§160(f ). 

B 

Sometimes a party to a labor dispute goes directly to a 

court—raising the specter that state law will say one thing 

about the conduct underlying the dispute while the NLRA

says another. It is a bedrock rule, of course, that federal 

law preempts state law when the two conflict. U. S. Const., 

Art. VI, cl. 2. Preemption under the NLRA is unusual,

though, because our precedent maintains that the NLRA 
 

Cite as: 598 U. S. ____ (2023) 3 

Opinion of the Court 

preempts state law even when the two only arguably conflict. San Diego Building Trades Council v. Garmon, 359 

U. S. 236, 245 (1959) (“When an activity is arguably subject 

to §7 or §8 of the [NLRA], the States as well as the federal

courts must defer to the exclusive competence of the National Labor Relations Board”). This doctrine—named Garmon preemption after the case that originated it—thus goes 

beyond the usual preemption rule. Under Garmon, States 

cannot regulate conduct “that the NLRA protects, prohibits, 

or arguably protects or prohibits.” Wisconsin Dept. of Industry v. Gould Inc., 475 U. S. 282, 286 (1986). 

Though broad, this standard has teeth. Longshoremen v. 

Davis, 476 U. S. 380, 394 (1986) (“The precondition for preemption, that the conduct be ‘arguably’ protected or prohibited, is not without substance”). It requires more than “a

conclusory assertion” that the NLRA arguably protects or 

prohibits conduct. Ibid. “[A] party asserting pre-emption 

must advance an interpretation of the [NLRA] that is not

plainly contrary to its language and that has not been ‘authoritatively rejected’ by the courts or the Board.” Id., at 

395. The party must then “put forth enough evidence to 

enable the court to find that the Board reasonably could uphold a claim based on such an interpretation.” Ibid. 

If the court determines that the party has met its burden

to show that “there is an arguable case for pre-emption,” it

generally must grant the party’s preemption defense and 

await the Board’s resolution of the legal status of the relevant conduct. Id., at 397.1 After that, “only if the Board 

—————— 1We have recognized exceptions to this rule. One allows a court to 

resolve a claim if the party raising it lacks a “reasonable opportunity” to 

secure a Board decision on the legal status of the conduct at issue. Sears, 

Roebuck & Co. v. Carpenters, 436 U. S. 180, 201 (1978); see also Davis, 

476 U. S., at 393, n. 10. Another applies if the conduct in question is “a 

merely peripheral concern” of the NLRA. San Diego Building Trades 

Council v. Garmon, 359 U. S. 236, 243 (1959). A third covers situations 
 

 

4 GLACIER NORTHWEST, INC. v. TEAMSTERS 

Opinion of the Court 

decides that the conduct is not protected or prohibited [by

the NLRA] may the court entertain the litigation.” Ibid. 

“[W]hen properly invoked,” Garmon thus “tells us not just

what law applies (federal law, not state law) but who applies it (the National Labor Relations Board, not the state

courts or federal district courts).” Trollinger v. Tyson 

Foods, Inc., 370 F. 3d 602, 608 (CA6 2004). 

C 

We relay the facts as alleged in the complaint. Glacier 

Northwest sells ready-mix concrete to customers in Washington State. Each batch must be mixed to the customer’s 

specifications. After Glacier combines the raw 

ingredients—cement, sand, aggregate, admixture, and 

water—in a hopper, it transfers the resulting concrete to

one of its trucks for prompt delivery. 

In this business, time is of the essence. Concrete is highly

perishable—it begins to harden immediately once at rest. 

Ready-mix trucks can preserve concrete in a rotating drum 

located on the back of the truck, but only for a limited time. 

If concrete remains in the rotating drum for too long, it will

harden and cause significant damage to the truck. Worse 

still, the hardening begins right away if the drum stops revolving.

The International Brotherhood of Teamsters Local Union 

No. 174 (Union) serves as the exclusive bargaining representative for Glacier’s truck drivers. After the collectivebargaining agreement between Glacier and the Union expired in the summer of 2017, the parties negotiated in an

attempt to reach a new deal. Things did not go smoothly. 

—————— 

“where the regulated conduct touche[s] interests so deeply rooted in local 

feeling and responsibility that, in the absence of compelling congressional direction,” a court cannot conclude that Congress “deprived the 

States of the power to act.” Id., at 244. Because we conclude that the 

NLRA does not arguably protect the Union’s conduct, we need not address these exceptions. 
 

Cite as: 598 U. S. ____ (2023) 5 

Opinion of the Court 

Tensions came to a head on the morning of August 11.

According to the allegations in Glacier’s complaint, a Union 

agent signaled for a work stoppage when the Union knew

that Glacier was in the midst of mixing substantial

amounts of concrete, loading batches into ready-mix trucks,

and making deliveries. Although Glacier quickly instructed

drivers to finish deliveries in progress, the Union directed 

them to ignore Glacier’s orders. At least 16 drivers who had 

already set out for deliveries returned with fully loaded

trucks. Seven parked their trucks, notified a Glacier representative, and either asked for instructions or took actions 

to protect their trucks. But at least nine drivers abandoned 

their trucks without a word to anyone.

Glacier faced an emergency. The company could not

leave the mixed concrete in the trucks because the concrete’s inevitable hardening would cause significant damage to the vehicles. At the same time, the company could

not dump the concrete out of the trucks at random because 

concrete contains environmentally sensitive chemicals. To 

top it all off, Glacier had limited time to solve this conundrum. 

A mad scramble ensued. Glacier needed to determine 

which trucks had concrete in them, how close the concrete 

in each truck was to hardening, and where to dump that 

concrete in an environmentally safe manner. Over the 

course of five hours, nonstriking employees built special 

bunkers and managed to offload the concrete. When all was 

said and done, Glacier’s emergency maneuvers prevented 

damage to its trucks. But the concrete that it had already

mixed that day hardened in the bunkers and became useless. 

Glacier sued the Union for damages in Washington state 

court. Relying on the allegations detailed above, Glacier 

claimed that the Union intentionally destroyed the company’s concrete and that this conduct amounted to commonlaw conversion and trespass to chattels. 
 

 

6 GLACIER NORTHWEST, INC. v. TEAMSTERS 

Opinion of the Court 

The Union moved to dismiss Glacier’s tort claims on the 

ground that the NLRA preempted them. In the Union’s 

view, the NLRA at least arguably protected the drivers’ conduct, so the State was powerless to hold the Union accountable for any of the strike’s consequences.

The trial court agreed with the Union. After the appellate court reversed, the Washington Supreme Court reinstated the trial court’s decision. In its view, “the NLRA 

preempts Glacier’s tort claims related to the loss of its concrete product because that loss was incidental to a strike 

arguably protected by federal law.” 198 Wash. 2d 768, 774, 

500 P. 3d 119, 123 (2021).

We granted certiorari to resolve whether the NLRA

preempts Glacier’s tort claims alleging that the Union intentionally destroyed its property during a labor dispute.

598 U. S. ___ (2022). 

II 

As the party asserting preemption, the Union bears the 

burden of (1) advancing “an interpretation of the [NLRA]

that is not plainly contrary to its language and that has not

been ‘authoritatively rejected’ by the courts or the Board,”

and then (2) putting forth “enough evidence to enable the 

court to find that” the NLRA arguably protects the drivers’ 

conduct. Davis, 476 U. S., at 395. The Union passes the 

first test but fails the second. 

All agree that the NLRA protects the right to strike but

that this right is not absolute. Brief for Petitioner 18; Brief 

for Respondent 21, 46, n. 14. The Board has long taken the

position—which both the Union and Glacier accept—that 

the NLRA does not shield strikers who fail to take “reasonable precautions” to protect their employer’s property from 

foreseeable, aggravated, and imminent danger due to the 

sudden cessation of work. Bethany Medical Center, 328 

N. L. R. B. 1094 (1999) (“concerted activity” is “indefensible 
 

Cite as: 598 U. S. ____ (2023) 7 

Opinion of the Court 

where employees fail to take reasonable precautions to protect the employer’s plant, equipment, or products from foreseeable imminent danger due to sudden cessation of work”);

see also Brief for Petitioner 14, 30–31; Brief for Respondent 

28–29; Reply Brief 6–7; Tr. of Oral Arg. 68, 86. Given this 

undisputed limitation on the right to strike, we proceed to

consider whether the Union has demonstrated that the 

statute arguably protects the drivers’ conduct. Davis, 476 

U. S., at 395. We conclude that it has not.2 

The drivers engaged in a sudden cessation of work that 

put Glacier’s property in foreseeable and imminent danger.

The Union knew that concrete is highly perishable and that 

it can last for only a limited time in a delivery truck’s rotating drum. It also knew that concrete left to harden in a 

truck’s drum causes significant damage to the truck. The 

Union nevertheless coordinated with truck drivers to initiate the strike when Glacier was in the midst of batching

large quantities of concrete and delivering it to customers. 

Predictably, the company’s concrete was destroyed as a result. And though Glacier’s swift action saved its trucks in

the end, the risk of harm to its equipment was both foreseeable and serious. See NLRB v. Special Touch Home Care 

Services, Inc., 708 F. 3d 447, 460 (CA2 2013) (“The appropriate inquiry is focused on the risk of harm, not its realization”).

The Union failed to “take reasonable precautions to protect” against this foreseeable and imminent danger. Bethany Medical Center, 328 N. L. R. B., at 1094. It could have 

—————— 2The Union moved to dismiss Glacier’s claims for failure to state a 

claim and for lack of subject matter jurisdiction. Like the Washington

Supreme Court, we treat both motions together and accept the allegations in the complaint as true at the motion-to-dismiss stage. 198 Wash. 

2d 768, 782–783, 500 P. 3d 119, 127 (2021); see also Kinney v. Cook, 159 

Wash. 2d 837, 842, 154 P. 3d 206, 209 (2007). Pursuant to Washington

law, we also may consider additional factual allegations made by Glacier

that support its complaint. See Bravo v. Dolsen Companies, 125 Wash. 

2d 745, 750, 888 P. 2d 147, 150 (1995). 
 

8 GLACIER NORTHWEST, INC. v. TEAMSTERS 

Opinion of the Court 

initiated the strike before Glacier’s trucks were full of wet 

concrete—say, by instructing drivers to refuse to load their

trucks in the first place. Once the strike was underway,

nine of the Union’s drivers abandoned their fully loaded

trucks without telling anyone—which left the trucks on a

path to destruction unless Glacier saw them in time to unload the concrete. Yet the Union did not take the simple 

step of alerting Glacier that these trucks had been returned. Nor, after the trucks were in the yard, did the Union direct its drivers to follow Glacier’s instructions to facilitate a safe transfer of equipment. To be clear, the 

“reasonable precautions” test does not mandate any one action in particular. But the Union’s failure to take even minimal precautions illustrates its failure to fulfill its duty. 

Indeed, far from taking reasonable precautions to mitigate foreseeable danger to Glacier’s property, the Union executed the strike in a manner designed to compromise the 

safety of Glacier’s trucks and destroy its concrete. Such 

conduct is not “arguably protected” by the NLRA; on the 

contrary, it goes well beyond the NLRA’s protections. See 

NLRB v. Marshall Car Wheel & Foundry Co., 218 F. 2d 409, 

411, 413 (CA5 1955) (strike unprotected when employees

abandoned their posts without warning “when molten iron 

in the plant cupola was ready to be poured off,” even though 

“a lack of sufficient help to carry out the critical pouring

operation might well have resulted in substantial property 

damage”).

Thus, accepting the complaint’s allegations as true, the

Union did not take reasonable precautions to protect Glacier’s property from imminent danger resulting from the

drivers’ sudden cessation of work. The state court thus 

erred in dismissing Glacier’s tort claims as preempted on 

the pleadings. 

III 

The Union resists this conclusion. First, it emphasizes 
Cite as: 598 U. S. ____ (2023) 9 

Opinion of the Court 

that the NLRA’s protection of the right to strike should “‘be 

given a generous interpretation.’” Brief for Respondent 21

(quoting NLRB v. Erie Resistor Corp., 373 U. S. 221, 234– 

235 (1963)). A strike, it points out, consists of a “concerted 

stoppage of work.” §142(2). So, the argument goes, by engaging in a concerted stoppage of work to support their economic demands, the drivers engaged in conduct arguably 

protected by §7 of the NLRA.

This argument oversimplifies the NLRA. As we explained, the right to strike is limited by the requirement 

that workers “take reasonable precautions to protect the 

employer’s plant, equipment, or products from foreseeable 

imminent danger due to sudden cessation of work.” Bethany Medical Center, 328 N. L. R. B., at 1094. So the mere 

fact that the drivers engaged in a concerted stoppage of

work to support their economic demands does not end the

analysis. We must also ask whether the strike exceeded the 

limits of the statute. 

Second, the Union argues that “workers do not forfeit the

Act’s protections simply by commencing a work stoppage at 

a time when the loss of perishable products is foreseeable.” 

Brief for Respondent 22. It points out that the Board has

found strikers’ conduct protected even when their decision

not to work created a risk that perishable goods would spoil. 

See, e.g., Lumbee Farms Coop., 285 N. L. R. B. 497 (1987) 

(raw poultry processing workers), enf ’d, 850 F. 2d 689 (CA4

1988); Central Oklahoma Milk Producers Assoc., 125 

N. L. R. B. 419 (1959) (milk-truck drivers), enf ’d, 285 F. 2d 

495 (CA10 1960); Leprino Cheese Co., 170 N. L. R. B. 601 

(1968) (cheese factory employees), enf ’d, 424 F. 2d 184

(CA10 1970). If the mere risk of spoilage is enough to render a strike illegal, the Union insists, then workers who 

deal with perishable goods will have no meaningful right to 

strike. 

The Union is swinging at a straw man. It casts this case 

as one involving nothing more than a foreseeable risk that 
 

 

10 GLACIER NORTHWEST, INC. v. TEAMSTERS 

Opinion of the Court 

the employer’s perishable products would spoil. But given

the lifespan of wet concrete, Glacier could not batch it until 

a truck was ready to take it. So by reporting for duty and 

pretending as if they would deliver the concrete, the drivers 

prompted the creation of the perishable product. Then, they

waited to walk off the job until the concrete was mixed and

poured in the trucks. In so doing, they not only destroyed 

the concrete but also put Glacier’s trucks in harm’s way.

This case therefore involves much more than “a work stoppage at a time when the loss of perishable products is foreseeable.” Brief for Respondent 22.

Third, the Union maintains that the timing of the strike

and Glacier’s lack of notice cannot render the drivers’ conduct unprotected. Id., at 26–28. It argues that workers are

not required to time their strikes to minimize economic

harm to their employer, see Lumbee Farms, 285 N. L. R. B., 

at 506, and that the NLRA does not impose a legal requirement that workers give specific notice of a strike’s timing, 

see Columbia Portland Cement Co. v. NLRB, 915 F. 2d 253, 

257 (CA6 1990).

We agree that the Union’s decision to initiate the strike

during the workday and failure to give Glacier specific notice do not themselves render its conduct unprotected. Still, 

they are relevant considerations in evaluating whether

strikers took reasonable precautions, whether harm to 

property was imminent, and whether that danger was foreseeable. See International Protective Services, Inc., 339 

N. L. R. B. 701, 702–703 (2003) (attempt “‘to capitalize on

the element of surprise’” stemming from a lack of notice

weighed in favor of concluding that a union failed to take 

reasonable precautions). In this instance, the Union’s 

choice to call a strike after its drivers had loaded a large 

amount of wet concrete into Glacier’s delivery trucks 

strongly suggests that it failed to take reasonable precautions to avoid foreseeable, aggravated, and imminent harm 

to Glacier’s property. 
 

 

 

Cite as: 598 U. S. ____ (2023) 11 

Opinion of the Court 

Finally, the Union points out that the drivers returned

the trucks to Glacier’s facility. And it maintains that all of 

the drivers left the drums of their trucks rotating, which

delayed the concrete’s hardening process. In the Union’s 

view, this establishes that the drivers took reasonable precautions to protect the trucks. Brief for Respondent 28–30. 

We see it differently. That the drivers returned the 

trucks to Glacier’s facility does not do much for the Union—

refraining from stealing an employer’s vehicles does not 

demonstrate that one took reasonable precautions to protect them. And Glacier’s allegations do not support the Union’s assertion that all of the drivers left the drums rotating.

The Union relies on a vague remark by an unspecified Union agent to another unspecified person to leave a truck 

running. See id., at 9, 30; Brief for Petitioner 8; App. 34.

This snippet does not show that all of the drivers left their

trucks running, and even if it did, that would not necessarily mean that the delivery trucks’ drums continued rotating. In any event, Glacier alleged that if concrete remains in a ready-mix truck for too long, it will harden and 

cause significant damage to the truck. The rotating drum

forestalls that hardening for a time, but not indefinitely.

And the Union concedes that the NLRA does not arguably 

protect its actions if they posed a material risk of harm to 

the trucks. Tr. of Oral Arg. 78.3 

—————— 3After the Washington Supreme Court affirmed the dismissal of Glacier’s tort claims, the Board’s general counsel issued a complaint alleging 

that Glacier engaged in unfair labor practices in relation to its labor dispute with the drivers, including by disciplining some of those involved in

the strike. The lower courts have not addressed the significance, if any, 

of the Board’s complaint with respect to Garmon preemption. We will 

not do so in the first instance. Cutter v. Wilkinson, 544 U. S. 709, 718, 

n. 7 (2005) (“[W]e are a court of review, not of first view”). The Board’s 

general counsel agrees that this issue is not properly before us. See Brief 

for United States as Amicus Curiae 28. 
 

12 GLACIER NORTHWEST, INC. v. TEAMSTERS 

Opinion of the Court 

* * * 

Glacier alleges that the drivers’ conduct created an emergency in which it had to devise a way to offload concrete “in

a timely manner to avoid costly damage to [its] mixer 

trucks.” App. 72. The Union’s actions not only resulted in

the destruction of all the concrete Glacier had prepared that

day; they also posed a risk of foreseeable, aggravated, and 

imminent harm to Glacier’s trucks. Because the Union took 

affirmative steps to endanger Glacier’s property rather

than reasonable precautions to mitigate that risk, the 

NLRA does not arguably protect its conduct. We reverse 

the judgment of the Washington Supreme Court and remand the case for further proceedings not inconsistent with

this opinion. 

It is so ordered. 
_________________ 

_________________ 

Cite as: 598 U. S. ____ (2023) 1 

THOMAS, J., concurring in judgment 

SUPREME COURT OF THE UNITED STATES 

No. 21–1449 

GLACIER NORTHWEST, INC., DBA CALPORTLAND, 

PETITIONER v. INTERNATIONAL BROTHERHOOD 

OF TEAMSTERS LOCAL UNION NO. 174 

ON WRIT OF CERTIORARI TO THE SUPREME COURT OF 

WASHINGTON 

[June 1, 2023]

 JUSTICE THOMAS, with whom JUSTICE GORSUCH joins,

concurring in the judgment. 

I agree that petitioner’s state-court claims are not preempted by the National Labor Relations Act (NLRA). The 

majority reaches this conclusion, however, by applying the 

Court’s precedent in San Diego Building Trades Council v. 

Garmon, 359 U. S. 236 (1959), which held that state courts

are disabled from adjudicating state-law claims that concern conduct “arguably” protected under the NLRA. Id., at 

245–246. Because this Court has previously held that the

type of conduct alleged here is not protected, I join JUSTICE 

ALITO’s opinion concurring in the judgment. I write separately to emphasize the oddity of Garmon’s broad pre-emption regime.

This Court typically applies a high bar before concluding 

that federal law “strip[s] state courts of jurisdiction to hear 

their own state claims.” Atlantic Richfield Co. v. Christian, 

590 U. S. ___, ___–___ (2020) (slip op., at 11–12). Likewise, 

the Court generally requires a “clear” purpose to displace 

state law before finding that a federal statute does so. Wyeth v. Levine, 555 U. S. 555, 565 (2009) (internal quotation

marks omitted). 

As the majority notes, however, Garmon “goes beyond the 

usual preemption rule.” Ante, at 3. In Garmon, the Court 
 

2 GLACIER NORTHWEST, INC. v. TEAMSTERS 

THOMAS, J., concurring in judgment 

determined that, “[w]hen an activity is arguably subject to 

§7 or §8 of the Act” (which, respectively, concern employees’ 

right to engage in concerted activity and unfair labor practices), “the States as well as the federal courts must defer

to the exclusive competence of the National Labor Relations 

Board [(NLRB or Board)].” 359 U. S., at 245. The Court 

went on to explain that this prophylactic rule of pre-emption may apply even to state-court claims arising under 

state private law (rather than the NLRA or a comparable 

state regulatory scheme) and even to claims seeking remedies not available from the Board. Id., at 246–248.* Nor, 

under the Court’s rule, is the State’s power to act restored

if the NLRB “fail[s] to determine the status of the disputed

conduct by declining to assert jurisdiction, or by refusal . . . 

to file a charge; or by adopting some other disposition which 

does not define the nature of the activity with unclouded 

legal significance.” Id., at 245–246. 

Garmon acknowledged that the NLRA’s pre-emption implications “‘are of a Delphic nature,’” leaving the States’ residual power in a “‘penumbral area [that] can be rendered 

progressively clear only by the course of litigation.’” Id., at 

240–241 (quoting Machinists v. Gonzales, 356 U. S. 617, 

619 (1958); Weber v. Anheuser-Busch, Inc., 348 U. S. 468, 

480–481 (1955)). It thus emphasized that “Congress has 

entrusted administration of the labor policy for the Nation

to a centralized administrative agency,” making it “essential to the administration of the Act” that determinations 

about protected and prohibited conduct “be left in the first 

—————— 

*Nonetheless, and motivated by “due regard for the presuppositions of

our embracing federal system,” Garmon carved out two areas of presumptive state control: (1) “where the activity regulated was a merely

peripheral concern of the [NLRA as amended],” and (2) where it “touched 

interests so deeply rooted in local feeling and responsibility that, in the

absence of compelling congressional direction, [the Court] could not infer 

that Congress had deprived the States of the power to act.” 359 U. S., at 

243–244. 
 

 

 

Cite as: 598 U. S. ____ (2023) 3 

THOMAS, J., concurring in judgment 

instance to the [NLRB].” 359 U. S., at 242, 244–245. To do 

otherwise, it feared, “would create potential frustration of

national purposes” and invite “the danger of state interference with national policy.” Id., at 244–245. 

Justice Harlan concurred in the result, warning that the

majority’s rule would “reduc[e] to the vanishing point”

States’ “power to redress wrongful acts in the labor field”

and provide any “effective remedy under their own laws for 

. . . tortious conduct.” Id., at 253–254. The years since have 

borne out that warning. Garmon elevates “even the remotest possibility of conflict,” thereby “overstat[ing ] the likelihood and significance of conflicts and . . . set[ting] up an unreal goal of doctrinal and factual harmony.” L. Jaffe, 

Primary Jurisdiction, 77 Harv. L. Rev. 1037, 1053 (1964).

In effect, “Garmon doctrine completely pre-empts statecourt jurisdiction unless the Board determines that the disputed conduct is neither protected nor prohibited by the 

[NLRA].” Sears, Roebuck & Co. v. Carpenters, 436 U. S. 

180, 199, n. 29 (1978). 

The majority opinion today underscores the strangeness 

of the Garmon regime. Here, the Supreme Court of the 

United States reassures a state court of its power to adjudicate a state-law tort claim. The Court does so, not based 

on its own judgment that federal law does not pre-empt the

claim, but because the NLRB’s existing precedents adequately remove any “[c]lou[d]” over the matter. 359 U. S., 

at 246. But, if the Board’s precedents left the matter “arguable” (and the NLRA did not plainly dictate an answer),

then the state courts would be “ousted” of jurisdiction. 

Longshoremen v. Davis, 476 U. S. 380, 396 (1986). The upshot of this approach appears to be that the scope of the 

NLRA’s pre-emption of state-court jurisdiction over state 

claims is defined—not by the statutory text—but by “penumbra[s]” that wax and wane as the Board develops, or 

declines to develop, its own carefully insulated common law 
 

4 GLACIER NORTHWEST, INC. v. TEAMSTERS 

THOMAS, J., concurring in judgment 

of labor relations. Garmon, 359 U. S., at 240 (internal quotation marks omitted).

The parties here have not asked us to reconsider Garmon, 

nor is it necessary to do so to resolve this case. Nonetheless, 

in an appropriate case, we should carefully reexamine

whether the law supports Garmon’s “unusual” pre-emption 

regime. Ante, at 2. In doing so, I would bear in mind that

any proper pre-emption inquiry must focus on the NLRA’s

text and ask whether federal law and state law “are in logical contradiction,” such that it is impossible to comply with

both. Merck Sharp & Dohme Corp. v. Albrecht, 587 U. S. 

___, ___ (2019) (THOMAS, J., concurring) (slip op., at 2); see

also PLIVA, Inc. v. Mensing, 564 U. S. 604, 617–618 (2011). 
ALITO, J., concurring

_________________ 

_________________ 

Cite as: 598 U. S. ____ (2023) 1 

ALITO, J., concurring in judgment 

SUPREME COURT OF THE UNITED STATES 

No. 21–1449 

GLACIER NORTHWEST, INC., DBA CALPORTLAND, 

PETITIONER v. INTERNATIONAL BROTHERHOOD 

OF TEAMSTERS LOCAL UNION NO. 174 

ON WRIT OF CERTIORARI TO THE SUPREME COURT OF 

WASHINGTON 

[June 1, 2023]

 JUSTICE ALITO, with whom JUSTICE THOMAS and 

JUSTICE GORSUCH join, concurring in the judgment. 

I agree with the Court that the Washington Supreme

Court erred in holding that Glacier Northwest’s complaint 

is preempted under San Diego Building Trades Council v. 

Garmon, 359 U. S. 236 (1959). The National Labor Relations Act (NLRA) protects the right to strike, but that right

is subject to certain limitations and qualifications, see 29

U. S. C. §163, and this Court’s decisions make clear that the 

Act does not protect striking employees who engage in the

type of conduct alleged here. 

This Court has long recognized that the Act does not “invest those who go on strike with an immunity from discharge for acts of trespass or violence against the employer’s property.” NLRB v. Fansteel Metallurgical Corp., 

306 U. S. 240, 255 (1939). To justify “despoiling [an employer’s] property” or “the seizure and conversion of its 

goods,” we have reasoned, “would be to put a premium on 

resort to force instead of legal remedies.” Id., at 253. It 

follows that Garmon preemption does not prevent States

from imposing liability on employees who intentionally destroy their employer’s property. See, e.g., Machinists v. 

Wisconsin Employment Relations Comm’n, 427 U. S. 132, 

136 (1976) (“Policing . . . destruction of property has been 
 

2 GLACIER NORTHWEST, INC. v. TEAMSTERS 

ALITO, J., concurring in judgment 

held most clearly a matter for the States”); Construction 

Workers v. Laburnum Constr. Corp., 347 U. S. 656, 669 

(1954) (The NLRA does not allow employees to “destroy 

property without liability for the damage done”); Electrical 

Workers v. Wisconsin Employment Relations Bd., 315 U. S. 

740, 748 (1942) (The NLRA “was not designed to preclude a

State” from regulating threats of property damage); see also 

Linn v. Plant Guard Workers, 383 U. S. 53, 61–62 (1966) 

(“‘[T]here is no ground for concluding that existing criminal 

penalties or liabilities for tortious conduct have been eliminated’” by the NLRA); Bill Johnson’s Restaurants, Inc. v. 

NLRB, 461 U. S. 731, 741–742 (1983) (“It has . . . repeatedly

been held that an employer has the right to seek local judicial protection from tortious conduct during a labor dispute”).

Nothing more is needed to resolve this case. Glacier’s 

complaint alleges that the Union and its members acted

“with the improper purpose to harm Glacier by causing [its]

batched concrete to be destroyed.” App. 10; accord, id., at 

14, 19–20. As the Court recognizes, they succeeded by 

“prompt[ing] the creation of the perishable product” and 

then ceasing work when the concrete was in a vulnerable 

state. Ante, at 10 (emphasis deleted); see App. 10–13. Because this Court has long rejected the Union’s claim that

this kind of conduct is protected, Garmon preemption does

not apply. See Longshoremen v. Davis, 476 U. S. 380, 395 

(1986).1 

—————— 1The Court wisely declines to address the argument on which JUSTICE 

JACKSON relies regarding the effect of the complaint before the NLRB on 

this litigation. See post, at 7–8. That argument represents a striking 

extension of Garmon preemption, which, as the Court notes, is already 

an “unusual” doctrine. See ante, at 3–4. If the state courts on remand 

dismiss this case on that ground, the decision, in my judgment, would be

a good candidate for a quick return trip here. 
 

_________________ 

_________________ 

Cite as: 598 U. S. ____ (2023) 1 

JACKSON, J., dissenting 

SUPREME COURT OF THE UNITED STATES 

No. 21–1449 

GLACIER NORTHWEST, INC., DBA CALPORTLAND, 

PETITIONER v. INTERNATIONAL BROTHERHOOD 

OF TEAMSTERS LOCAL UNION NO. 174 

ON WRIT OF CERTIORARI TO THE SUPREME COURT OF 

WASHINGTON 

[June 1, 2023]

 JUSTICE JACKSON, dissenting. 

The right to strike is fundamental to American labor law.

Congress enshrined that right in the National Labor Relations Act (NLRA) and simultaneously established the National Labor Relations Board to adjudicate disputes that

arise between workers and management. That decision reflected Congress’s judgment that an agency with specialized expertise should develop and enforce national labor 

law in a uniform manner, through case-by-case adjudication. For its part, this Court has scrupulously guarded the

Board’s authority for more than half a century. See San 

Diego Building Trades Council v. Garmon, 359 U. S. 236 

(1959). Under Garmon, and as relevant here, a court presented with a tort suit based on strike conduct generally

must pause proceedings and permit the Board to determine 

in the first instance whether the union’s conduct is lawful 

if the conduct at issue is even “arguably” protected by the 

NLRA. Id., at 245. 

Today, the Court falters. As the majority acknowledges,

the Board’s General Counsel has filed a complaint with the 

Board after a thorough factual investigation, and that complaint alleges that the NLRA protects the strike conduct at 

the center of this state-court tort suit. The logical implication of a General Counsel complaint under Garmon is that 
 

2 GLACIER NORTHWEST, INC. v. TEAMSTERS 

JACKSON, J., dissenting 

the union’s conduct is at least arguably protected by the 

NLRA. Consequently, where (as here) there is a General

Counsel complaint pending before the Board, courts—including this Court—should suspend their examination. 

Garmon makes clear that we have no business delving into

this particular labor dispute at this time. 

But instead of modestly standing down, the majority eagerly inserts itself into this conflict, proceeding to opine on 

the propriety of the union’s strike activity based on the facts

alleged in the employer’s state-court complaint. As part of 

this mistaken expedition, the majority tries its own hand at

applying the Board’s decisions to a relatively novel scenario 

that poses difficult line-drawing questions—fact-sensitive

issues that Congress plainly intended for the Board to address after an investigation. And in the course of inappropriately weighing in on the merits of those questions at this

stage, the majority also misapplies the Board’s cases in a 

manner that threatens to both impede the Board’s uniform

development of labor law and erode the right to strike. 

In my view, today’s misguided foray underscores the wisdom of Congress’s decision to create an agency that is

uniquely positioned to evaluate the facts and apply the law 

in cases such as this one. This case is Exhibit A as to why

the Board—and not the courts—should ordinarily take the 

first crack at resolving contentious, fact-bound labor disputes of this nature. Because the majority’s ruling suggests

otherwise, I respectfully dissent. 

I 

The majority’s brief opinion quotes Garmon’s “arguably 

protected” test and endeavors to apply it. Ante, at 3–4, 6– 

11. But the opinion devotes relatively little space to the origins and purpose of that longstanding precedent. That 

omission is telling. A proper understanding of Garmon’s 

foundation sheds considerable light on the majority’s sequential missteps in this case. 
 

Cite as: 598 U. S. ____ (2023) 3 

JACKSON, J., dissenting 

A 

Congress’s passage of the NLRA “marked a fundamental

change in the Nation’s labor policies.” Sears, Roebuck & Co. 

v. Carpenters, 436 U. S. 180, 190 (1978). Prior to that point, 

union activity had been viewed as “a species of ‘conspiracy,’” prompting substantial conflict between labor and 

management. Ibid. With the enactment of the NLRA in 

1935, “Congress expressly recognized that collective organization of segments of the labor force into bargaining units

capable of exercising economic power comparable to that

possessed by employers may produce benefits for the entire

economy in the form of higher wages, job security, and improved working conditions.” Ibid. 

The heart of the NLRA is §7, which safeguards workers’ 

rights “to self-organization, to form, join, or assist labor organizations, to bargain collectively through representatives

of their own choosing, and to engage in other concerted activities for the purpose of collective bargaining or other mutual aid or protection.” 29 U. S. C. §157. Among the “‘concerted activities’” that the Act unquestionably protects is

“the vital, economic instrumen[t] of the strike.” Garmon, 

359 U. S., at 241; see §163.

Section 8 of the NLRA provides a list of “unfair labor

practice[s]” that employers and unions are prohibited from

engaging in. §158. For example, it is an unfair labor practice for an employer to “interfere with, restrain, or coerce 

employees in the exercise of ” their §7 rights, including the 

right to strike. §158(a)(1). And it is an unfair labor practice 

for a union to “refuse to bargain collectively with an employer.” §158(b)(3). Taken together, §7 and §8 establish 

certain conduct that Congress has deemed protected (§7)

and prohibited (§8). 

B 

Congress could have stopped there. But “Congress did 

not merely lay down a substantive rule of law to be enforced 
 

 

4 GLACIER NORTHWEST, INC. v. TEAMSTERS 

JACKSON, J., dissenting 

by any tribunal competent to apply law generally to the parties.” Garner v. Teamsters, 346 U. S. 485, 490 (1953). Rather, Congress “went on to confide primary interpretation

and application of its rules to a specific and specially constituted tribunal”: the National Labor Relations Board. 

Ibid.; see generally §§153–156. 

By statutory mandate, the Board is composed of five

members who are appointed by the President with the advice and consent of the Senate. §153(a). Congress also provided for an independent General Counsel, who is likewise

presidentially appointed and Senate confirmed. §153(d); 

see NLRB v. Food & Commercial Workers, 484 U. S. 112, 

117–118 (1987). The General Counsel conducts investigations into unfair labor practices and brings complaints before the Board through a “particular procedure” that Congress has prescribed “for investigation, complaint and

notice, and hearing and decision, including judicial relief 

pending a final administrative order” from the Board. Garner, 346 U. S., at 490; see §§153, 160. 

The Board has fleshed out this process via rulemaking 

authority that Congress has delegated. §156. If a person 

believes that an employer or union has committed an unfair 

labor practice, the person may file a charge with a regional

director, who acts on behalf of the General Counsel. 29 CFR 

§101.2 (2022). The regional director investigates the 

charge. §101.4. If “the charge appears to have merit and 

efforts to dispose of it by informal adjustment are unsuccessful,” the regional director issues a complaint on behalf 

of the General Counsel. §101.8. When a General Counsel’s 

complaint issues, an administrative law judge (ALJ) holds

a hearing and issues a decision, which the Board reviews if 

any party files an exception. §§101.8–101.12. If the Board 

finds that a party has engaged in an unfair labor practice, 

it must order the party to “cease and desist” and to take 

“such affirmative action . . . as will effectuate the policies” 

of the NLRA. 29 U. S. C. §160(c). 
Cite as: 598 U. S. ____ (2023) 5 

JACKSON, J., dissenting 

C 

The history and structure of the NLRA make clear that

Congress “entrusted administration of the labor policy for

the Nation to a centralized administrative agency”—the

Board—“armed with its own procedures, and equipped with 

its specialized knowledge and cumulative experience.” Garmon, 359 U. S., at 242. Congress thought the Board’s primary role was “necessary to obtain uniform application of

[the NLRA’s] substantive rules and to avoid th[e] diversities and conflicts likely to result from a variety of local procedures and attitudes toward labor controversies.” Garner, 

346 U. S., at 490. That judgment makes perfect sense. The 

NLRA’s substantive principles are intrinsically broad and

potentially conflicting, leaving much for future articulation

through case-by-case adjudication. Drawing the line between activities that constitute a protected strike, on the 

one hand, and unprotected actions for which employers may 

validly discipline employees, on the other, is a legally and 

factually complex task. Moreover, that task implicates important economic policy considerations about the relative 

bargaining power of labor and management that affect not 

only the parties to a particular labor dispute but also our

broader national economy. 

To effect Congress’s intent, this Court has consistently

recognized that “courts are not primary tribunals to adjudicate [these] issues.” Garmon, 359 U. S., at 244. Rather, “it 

is to the Board that Congress entrusted the task of applying 

the Act’s general . . . language in the light of the infinite 

combinations of events which might be charged as violative

of its terms.” Beth Israel Hospital v. NLRB, 437 U. S. 483, 

500–501 (1978) (internal quotation marks omitted). And 

the Board, “if it is to accomplish the task which Congress

set for it, necessarily must have authority . . . to fill the interstices of the broad statutory provisions.” Id., at 501. So, 

while the Board’s decision “is not the last word” on these 
 

6 GLACIER NORTHWEST, INC. v. TEAMSTERS 

JACKSON, J., dissenting 

complex matters—given that its decisions are subject to review in federal court—“it must assuredly be the first.” Marine Engineers v. Interlake S. S. Co., 370 U. S. 173, 185 

(1962) (emphasis added).

For that reason, this Court has long held that courts presented with claims arising out of a labor dispute must sometimes pause their proceedings to permit the Board to consider the dispute in the first instance. As relevant here, we 

have held that if §7—including its protection of the right to 

strike—“arguably” protects the conduct at issue in a statecourt suit, then the court must await the Board’s word as to 

whether the conduct is, in fact, protected. Garmon, 359 

U. S., at 245. 

To determine whether conduct is “arguably protected,” a

state court examines the showing of the party invoking Garmon and seeking to pause the litigation. The court asks 

whether that party has (1) “advance[d] an interpretation of 

the [NLRA] that is not plainly contrary to its language and 

that has not been ‘authoritatively rejected’ by the courts or

the Board,” and (2) “put forth enough evidence to enable the 

court to find that the Board reasonably could uphold a claim 

based on such an interpretation.” Longshoremen v. Davis, 

476 U. S. 380, 395 (1986). If so, the state court must pause 

proceedings to allow the Board to consider the complex legal

and factual contours of the question whether the union’s

conduct is actually protected by the NLRA.

The majority refers to this as “Garmon preemption,” in

keeping with historical practice. Ante, at 3. But the term 

“preemption” is something of a misnomer. Rather than entirely and automatically precluding the state-court suit, the 

rule instead requires state courts to take a “jurisdictional

hiatus” while the Board considers the dispute in the first 

instance. Sears, Roebuck & Co., 436 U. S., at 203. If the 

Board determines (subject to judicial review) that §7 protects the union’s conduct, normal conflict preemption kicks 

in: A state court may not hold a union liable on state-law 
 

 

Cite as: 598 U. S. ____ (2023) 7 

JACKSON, J., dissenting 

claims for conduct that is protected by the NLRA. See 

Brown v. Hotel Employees, 468 U. S. 491, 503 (1984). But 

“if the Board decides that the conduct is not protected,” the

state court may proceed to “entertain the litigation.” Davis, 

476 U. S., at 397.1 

With these general principles in mind, I now turn to the 

particulars of this case. 

II 

This suit arises out of a union-organized strike. Petitioner Glacier Northwest is a concrete-delivery company,

and respondent International Brotherhood of Teamsters 

Local Union No. 174 (Union) represents Glacier’s concretedelivery truckdrivers. After the drivers went on strike, 

Glacier sent disciplinary letters to some of the drivers. The 

Union filed an unfair labor practice charge with the Board, 

alleging that the disciplinary letters were unlawful retaliation against the drivers for engaging in strike conduct that

is protected by the NLRA.

Glacier then filed a complaint in Washington state court, 

alleging that the Union engaged in tortious conduct when

it instructed the drivers to strike at a time when there was 

wet concrete in some of the company’s delivery trucks. In 

response, the Union filed another Board charge, maintaining that Glacier’s lawsuit constituted additional unlawful

retaliation. 

—————— 1 JUSTICE THOMAS seeks to undercut our Garmon precedent by describing it as “od[d]” and “strang[e]” relative to “ ‘the usual preemption rule.’ ” 

Ante, at 1, 3 (opinion concurring in judgment). But, as discussed, the 

Garmon rule is not a standard preemption doctrine; it is different because it is doing different work. Garmon protects Congress’s judgment

that the Board, not state or federal courts, should be generally responsible for the development of our Nation’s labor law. The required pause 

when Garmon’s “arguably protected” test is satisfied allows for efficient 

resolution of the dispute prior to the expenditure of state judicial resources, and the temporary nature of the pause makes it narrower, not 

broader, in effect than ordinary preemption. 
 

8 GLACIER NORTHWEST, INC. v. TEAMSTERS 

JACKSON, J., dissenting 

With respect to Glacier’s tort suit, the Washington courts

engaged in the standard Garmon inquiry, ultimately resulting in a determination by the Washington Supreme Court 

that the lawsuit could not proceed because the Union’s 

strike conduct was arguably protected by the NLRA. Glacier sought, and we granted, certiorari to review that decision. Notably, however, after the Washington Supreme 

Court issued its decision, the regional director acting on behalf of the Board’s General Counsel filed an administrative 

complaint against Glacier. In my view, for the reasons explained below, that subsequent event has greatly simplified 

the Garmon question. 

A 

The filing of the General Counsel’s administrative complaint necessarily suffices to establish that the Union’s 

strike conduct is “arguably protected” within the meaning

of Garmon. Thus, the General Counsel’s complaint should 

have marked the end of any court involvement in this matter at this time. 

The General Counsel’s complaint alleges that Glacier interfered with strike conduct protected by §7 when it disciplined its drivers for walking off the job and when it filed 

this tort suit. That complaint represents the General Counsel’s conclusion—reached after an extensive independent 

investigation involving collecting testimony and other evidence, and after careful consideration of the competing legal principles and policy concerns—that the Union’s claim

that its strike conduct was protected “appears to have 

merit.” 29 CFR §§101.4, 101.8. One “cannot credibly contend that a claim that makes it through this gauntlet does

not concern conduct ‘arguably’ protected by the NLRA.” Davis Supermarkets, Inc. v. NLRB, 2 F. 3d 1162, 1179 (CADC 

1993); accord, Makro, Inc., 305 N. L. R. B. 663, 670 (1991). 

A court presented with a General Counsel complaint

should therefore find Garmon inherently satisfied. This is 
 

Cite as: 598 U. S. ____ (2023) 9 

JACKSON, J., dissenting 

so because the entire point of Garmon’s arguably-protected

test is to permit the court to assess the facts and relevant

labor law in service of a gatekeeping function. The answer 

to the Garmon question simply (and solely) establishes 

whether the court can continue to entertain a lawsuit that 

relates to the challenged strike conduct, or whether the legal action must be suspended to allow the Board to make

an initial assessment of the matter. The court evaluates 

the existing evidence and the law for a specific reason: to

determine whether the lawsuit attacks arguably-protected 

conduct such that entertaining the legal action will interfere with the Board’s prerogative to develop the facts and

adjudicate the merits of the dispute as part of the Board’s 

broader authority to develop national labor law.

If the General Counsel investigates the matter and files

a complaint with the Board alleging that the union’s conduct is protected, it becomes indisputable that the pending 

legal action might interfere with the Board’s authority.

Thus, a General Counsel complaint relieves the court of the 

burden of having to make the arguably-protected assessment based on its own understanding of the evidence and 

labor law—it is “arguable” that the union’s conduct is protected because the General Counsel is arguing just that. To 

be sure, we have said that the arguably-protected test is

“not without substance” and is “not satisfied by a conclusory

assertion of pre-emption.” Davis, 476 U. S., at 394. But an 

allegation from the Board’s General Counsel after a thorough investigation is a far cry from a “conclusory assertion” 

of protection.2 

What is more, by virtue of the General Counsel’s complaint, the Board is, at this very moment, exercising its authority to adjudicate the merits of this dispute. On January 

—————— 2This is not to suggest that the General Counsel’s complaint is the end 

of the story, as the Board may ultimately disagree with the factual or

legal basis of that pleading. But the complaint is surely sufficient to establish arguable protection, such that a court should stay its hand. 
 

 

10 GLACIER NORTHWEST, INC. v. TEAMSTERS 

JACKSON, J., dissenting 

12, 2023, an ALJ denied Glacier’s motion to postpone the 

ALJ hearing on the General Counsel’s complaint pending 

this Court’s decision in this case. As the ALJ explained, the

General Counsel’s pleading “constituted a determination 

that the strikers’ conduct was at least arguably protected 

by [the NLRA] and that this agency became the exclusive 

forum for adjudicating whether the strikers’ conduct was 

protected.”3 A nine-day hearing ensued, and the parties

completed posthearing briefing last week. We have said 

that “the need for protecting the exclusivity of [the Board’s] 

jurisdiction is obviously greatest when the precise issue 

brought before a court is in the process of litigation through 

procedures originating in the Board.” Marine Engineers, 

370 U. S., at 185. That is exactly the situation here. 

For these reasons, I believe that the filing of the General 

Counsel’s complaint is more than sufficient to trigger Garmon’s pause, and that it must be so if consistency with Congress’s intent to give the Board primary authority to interpret and enforce the NLRA is to be maintained. In 

circumstances like these, “the States as well as the federal 

courts must defer to the exclusive competence of the National Labor Relations Board.” Garmon, 359 U. S., at 245. 

And this Court is no exception. Because the General Counsel has now filed a complaint with the Board concerning the 

labor dispute at issue in this case, all courts—including this 

one—should stand down. 

B 

The majority does not take issue with my conclusion that

the General Counsel’s complaint triggers a Garmon hiatus; 

instead, it takes no position on the matter, leaving the question open for the Washington courts to decide on remand. 

Ante, at 11, n. 3. 

—————— 3Order Denying Motion for Postponement of Hearing in Glacier Northwest, Inc., Nos. 19–CA–203068, 19–CA–211776, p. 7. 
Cite as: 598 U. S. ____ (2023) 11 

JACKSON, J., dissenting 

The majority’s reason for declining to address this argument is noteworthy. It explains that, because the General

Counsel’s complaint was filed after the Washington Supreme Court had affirmed the dismissal of Glacier’s complaint on Garmon grounds, “[t]he lower courts have not addressed the significance, if any, of the Board’s complaint 

with respect to Garmon preemption.” Ante, at 11, n. 3. And 

since we are “‘a court of review, not of first view,’” ibid. 

(quoting Cutter v. Wilkinson, 544 U. S. 709, 718, n. 7 

(2005)), the majority declines to “do so in the first instance.” 

Ante, at 11, n. 3. 

This rationale is inconsistent with the broader approach

that the majority takes in this case. It would be one thing 

if the Court simply noted the filing of the General Counsel’s

complaint and authorized the lower courts to evaluate the 

impact of that complaint on the Garmon question in the 

first instance. But it goes further: The majority also inserts

itself into the midst of this labor dispute now (despite the

General Counsel’s complaint), proceeding to apply the

Board’s cases to novel and difficult line-drawing questions

and ultimately concluding that the strike conduct alleged

in Glacier’s complaint is not even arguably protected.

The majority cannot have it both ways. A concern about 

the Court’s institutional role justifies, at most, vacating the 

judgment below and remanding for the lower court to consider the import of the General Counsel’s complaint. The 

same observation that compels the majority to allow for 

such lower-court consideration—that we are “‘a court of review, not of first view,’” ante, at 11, n. 3—should have likewise led it to decline to intrude into this labor dispute while 

it is pending before the Board. 

III 

For the reasons discussed above, I would have vacated 

the Washington Supreme Court’s judgment and remanded 
 

 

 

12 GLACIER NORTHWEST, INC. v. TEAMSTERS 

JACKSON, J., dissenting 

with directions to stay proceedings or dismiss Glacier’s complaint without prejudice, on the straightforward ground

that the General Counsel’s complaint triggers the jurisdictional hiatus that Garmon requires.4 

The majority sidesteps my preferred resolution of this

matter and instead proceeds to engage in Garmon’s “arguably protected” test by applying a series of fact-intensive

Board decisions to the bare allegations in Glacier’s statecourt complaint. To do this, the majority invokes the 

Board’s “reasonable precautions” principle. Ante, at 6–8. 

That principle (discussed in Part IV, infra) is derived from

the Board’s determination that striking workers must take 

reasonable precautions to protect persons, the employer’s

premises, and its equipment from foreseeable, aggravated, 

and imminent harm due to the sudden cessation of work. 

The majority has taken it upon itself to apply the Board’s 

reasonable-precautions principle to the factual allegations

about the Union’s conduct that Glacier alleges in this lawsuit, and it thereby concludes that the drivers’ conduct is

not even arguably protected by the NLRA.

This course of action (which is already confounding given

that the Board itself is currently considering the challenged 

strike conduct with the benefit of developed facts and labor 

law expertise) reflects an analytical approach to the issues 

presented that cannot be squared with Garmon. 

A 

Whether the NLRA protects particular strike conduct often turns on subtle factual disputes and nuanced legal distinctions. Here, for example, whether the Union’s strike 

conduct is protected or unprotected might well depend on 

—————— 4The Washington Supreme Court affirmed the dismissal of Glacier’s 

claims. Because only a pause of the state-court litigation is necessary 

under Garmon, the proper disposition is either a stay of proceedings or 

dismissal without prejudice. 
Cite as: 598 U. S. ____ (2023) 13 

JACKSON, J., dissenting 

whether the drivers left the concrete-delivery trucks’ revolving drums turning when they walked off the job. So, 

too, might it depend on fine legal gradations concerning 

how imminent or how aggravated the risk of harm must be

to trigger the duty to take reasonable precautions. These 

kinds of determinations cry out for evidentiary hearings, 

and in this highly fact-sensitive area of the law, which generally develops on a case-by-case basis, the scope of NLRA 

protection in a given set of circumstances is typically determined once the facts have been established—through discovery, debate, and sometimes the tedious work of making 

contentious credibility determinations.

Fortunately, in this regard, Congress has gifted our legal

system with an expert agency that thoroughly investigates 

what happened—i.e., the facts of strike-related labor disputes—and then engages in the initial task of answering 

the sometimes complex, always fact-bound question

whether the NLRA protects the strike conduct at issue. 

Meanwhile, a court that is undertaking Garmon’s arguablyprotected analysis is engaged in a fundamentally different 

inquiry. As explained in Part II–A, supra, while the court 

is most certainly considering strike conduct arising from a

labor dispute, it is not meant to address the merits of these 

complex questions. Under the NLRA and Garmon, courts 

must take as a given that the Board is the entity to which

Congress has assigned responsibility for initially determining what happened and taking the first crack at deciding

whether the NLRA protects the union’s conduct. And far 

from usurping that Board function, Garmon tasks the court 

with merely conducting a threshold, gatekeeping assessment of whether the lawsuit before it must be paused, or

whether the suit can proceed because it is not even arguable

that the conduct at issue in the lawsuit is protected by the 

NLRA. 

To avoid veering into the Board’s assigned territory, it is

crucial that the courts have a clear understanding of the 
 

 

 

14 GLACIER NORTHWEST, INC. v. TEAMSTERS 

JACKSON, J., dissenting 

nature of the Garmon assessment and what it requires.

The court asks, first of all, whether the party invoking Garmon has “advance[d] an interpretation of the [NLRA] that 

is not plainly contrary to its language and that has not been 

‘authoritatively rejected’ by the courts or the Board.” Davis, 

476 U. S., at 395. This inquiry involves merely comparing 

the union’s claim about the scope of its protection to the

broad protective language of the statute and deciding

whether the union’s interpretation has already been definitively rejected either by courts or by the Board. 

The second task is to determine whether the party invoking Garmon has “put forth enough evidence to enable the 

court to find that the Board reasonably could uphold a claim 

based on such an interpretation.” Davis, 476 U. S., at 395. 

Again, this is not an invitation to supplant the Board’s factfinding role or to usurp the authority that Congress has 

given the Board to make the initial underlying protectedor-unprotected determination. Rather, the point of this

part of the Garmon assessment is simply to determine

whether it is arguable that the Board—in the exercise of its 

discretion to develop labor law and aided by its investigation into the facts—could conclude that the strike conduct 

at issue is protected by the NLRA. See 359 U. S., at 245. 

Thus, consistent with a statutory scheme that gives primacy to the agency’s expertise, a court’s task under Garmon 

is unmistakably modest. It must merely assess whether, in 

light of existing law and the evidence that has been 

amassed related to this strike, it is possible that the union 

could prevail before the Board. Put another way, instead of 

stepping into the Board’s shoes as primary factfinder, or

even prognosticating about what the Board is likely to decide concerning the extent of NLRA coverage, a court that

stands down upon a proper Garmon analysis has simply determined (1) that existing law does not plainly and authoritatively prohibit the strike conduct at issue, and (2) that

evidence exists concerning how the strike was conducted 
Cite as: 598 U. S. ____ (2023) 15 

JACKSON, J., dissenting 

that might ultimately favor the union, such that the lawsuit 

should pause to allow the Board to gather the facts and apply its expertise to determine whether the strike was lawful. 

B 

The majority seems to misunderstand all this in the context of this case. It correctly concludes that the Union has 

carried its burden of “advancing an interpretation of the

[NLRA] that is not plainly contrary to its language and that 

has not been authoritatively rejected by the courts or the

Board.” Ante, at 6 (internal quotation marks omitted). But 

it finds that the Union has failed to satisfy the second Garmon step, and it does so after undertaking its own assessment of the facts alleged in Glacier’s complaint and endeavoring to apply the Board’s fact-bound reasonableprecautions precedents. See, e.g., ante, at 7 (determining, 

based on alleged facts, that “[t]he drivers engaged in a sudden cessation of work that put Glacier’s property in foreseeable and imminent danger” and that the risk of harm to the 

concrete-delivery trucks was “both foreseeable and serious”); ibid. (concluding that “[t]he Union failed to ‘take reasonable precautions,’” after hypothesizing various steps 

that, according to the majority, the Union should have 

taken but did not).

Given what I have already said about Garmon’s purpose

and what it calls for, the majority’s error in proceeding in 

this fashion is obvious. To my mind, if a court that is evaluating what to do per Garmon finds itself weighing in on

such fact-bound matters as whether the strike posed a risk

of harm that was aggravated enough or imminent enough 

to remove NLRA protection, or starts contemplating 

whether the precautions that the striking employees took 

to address any such risk were reasonable enough to allow 

them to retain the right to strike, it has unwittingly wandered into a domain that Congress intentionally assigned 
 

16 GLACIER NORTHWEST, INC. v. TEAMSTERS 

JACKSON, J., dissenting 

to the Board to address in the first instance.5 

It is clear to me that Congress plainly intended for the

Board’s factfinding function to be at the forefront of this 

kind of legal evaluation. Thus, in my view, when a court

undertakes the Garmon analysis in a context such as this

one, it should take care to limit itself to its own assigned 

responsibility: the mere determination of whether, given

the union’s evidence and legal interpretation, the Board 

could possibly conclude that the union had taken reasonable precautions. If yes, the court should suspend the pending legal action to let the Board decide the question. To 

conclude no, given the fact-bound nature of the reasonableprecautions analysis, a court in all but the most exceptional 

circumstances will need to be able to point to a reasonableprecautions case from the Board that is on all fours with the 

facts of the case before it and that found the conduct unprotected. In that circumstance, the court can proceed with the 

suit, without breaking new legal ground on the scope of the 

right to strike. 

In all events, then, courts can properly decide the Garmon issue without making law in this area, precisely as 

Congress intended. Indeed, I think we best respect congressional intent regarding the Board’s authority to develop 

uniform labor law by leaving the application of the Board’s 

reasonable-precautions principle to the Board itself. The 

majority’s contrary approach opens up the possibility that 

courts around the country will now act on bare allegations 

—————— 5 Justice Blackmun warned that a formulation of the Garmon test that 

directs attention to a party’s evidence might lead some courts to make 

such an errant assessment, “under the guise of weighing the sufficiency 

of the evidence.” Longshoremen v. Davis, 476 U. S. 380, 404 (1986) (opinion concurring in part and dissenting in part) (expressing the concern 

that a future court might misunderstand its role and mistakenly undertake “[to] mak[e] precisely the determination that Garmon makes clear 

is for the Board, and only the Board, to make”). That warning was prescient. 
 

Cite as: 598 U. S. ____ (2023) 17 

JACKSON, J., dissenting 

to generate conflicting results about the contours of the venerated right to strike, which, ironically, was the primary 

concern that motivated Congress to create the Board in the

first place. 

IV 

For what it’s worth, even if the majority’s approach to deciding the Garmon question were the correct one, the majority misapplies the reasonable-precautions principle to

the allegations here in a manner that threatens to impinge

on the right to strike and on the orderly development of labor law. 

A 

1 

A strike, by definition, is a “concerted stoppage of work 

by employees,” or “any concerted slowdown or other concerted interruption of operations by employees.” §142(2).

When employees stop working, production may halt, deliveries may be delayed, and services may be canceled. At the 

risk of stating the obvious, this means that the workers’ 

right to strike inherently includes the right to impose economic harm on their employer. 

Congress was well aware that organized labor’s exercise 

of the right to strike risks harm to an employer’s economic

interests. See §151; NLRB v. Erie Resistor Corp., 373 U. S. 

221, 234 (1963) (Congress’s protection of the right to strike

reflects its understanding that strikes are authorized “economic weapon[s]”). Yet, Congress protected that right anyway. In fact, the threat of economic harm posed by the right 

to strike is a feature, not a bug, of the NLRA. The potential

pain of a work stoppage is a powerful tool, and one that unquestionably advances Congress’s codified goal of achieving 

“equality of bargaining power between employers and employees.” §151. Unions leverage a strike’s economic harm 

(or the threat of it) into bargaining power, and then wield 
 

 

18 GLACIER NORTHWEST, INC. v. TEAMSTERS 

JACKSON, J., dissenting 

that power to demand improvement of employees’ wages 

and working conditions—goals that, according to Congress, 

benefit the economy writ large. See Sears, Roebuck & Co., 

436 U. S., at 190. 

Still, the right to strike is, of course, not unlimited. But 

when “Congress chose to qualify the use of the strike, it did 

so by prescribing the limits and conditions of the abridgment in exacting detail.” Erie Resistor, 373 U. S., at 234. 

Section 8 enumerates several limitations. For example, a 

union must notify an employer that it intends to terminate 

or modify its contract—and thus that a strike is possible—

at least 60 days before striking. §158(d). A union cannot 

strike for unlawful purposes, such as putting economic

pressure on parties other than the primary employer.

§158(b)(4)(i)(B). And, in certain healthcare settings, unions 

must provide at least 10 days’ notice of the precise date and 

time of a strike. §158(g).

Additionally, §163 of the NLRA (which Congress added 

via the 1947 Taft-Hartley Amendments, 61 Stat. 151) states

that “nothing in this subchapter, except as specifically provided for herein, shall be construed so as either to interfere 

with or impede or diminish in any way the right to strike,

or to affect the limitations or qualifications on that right.” 

Thus, the text of the NLRA allows for only two kinds of

limitations on the right to strike: those enumerated in the 

Act itself, and the “limitations or qualifications” on the 

right that existed when the Taft-Hartley Amendments were

enacted. See NLRB v. Drivers, 362 U. S. 274, 281–282 

(1960). The only relevant limitation here is the one set out

in NLRB v. Fansteel Metallurgical Corp., 306 U. S. 240 

(1939).6 

—————— 6The Senate Report accompanying the Taft-Hartley Amendments explained the four kinds of pre-existing “limitations or qualifications” on

the right to strike that Congress had in mind in §163, which were drawn

from decisions of the Board and this Court. See S. Rep. No. 105, 80th

Cong., 1st Sess., 28 (1947); Drivers, 362 U. S., at 281–282. The three 
Cite as: 598 U. S. ____ (2023) 19 

JACKSON, J., dissenting 

Our Fansteel decision stands for the principle that “employees ha[ve] the right to strike but they ha[ve] no license 

to commit acts of violence or to seize their employer’s plant.” 

Id., at 253. The facts of that case involved 95 striking employees who effected a “sit-down strike by taking over and 

holding two of [their employer’s] key buildings.” Id., at 248 

(internal quotation marks omitted). The employees subsequently engaged in “a pitched battle” in which they “resisted the attempt by the sheriff to evict and arrest them.” 

Id., at 249. We held that the NLRA did not condone this 

conduct, which would “put a premium on resort to force”

and would “subvert the principles of law and order which

lie at the foundations of society.” Id., at 253. 

Congress’s incorporation of Fansteel’s limitation into the 

NLRA establishes that, while employees have the right to 

withhold their labor peaceably, subsequent affirmative acts

of violence, or seizure of an employer’s premises, are not 

protected labor practices. 

2 

As a general matter, the dispute in this case is over 

whether employees can withhold their labor if doing so 

risks damage to their employer’s property. As explained

above, by carefully restricting limitations on the right to

strike in the NLRA itself, Congress has indicated that the

act of peacefully walking off the job is protected strike conduct even if economic harm incidentally results. What is 

not protected is any subsequent affirmative step to destroy

or seize the employer’s property. This is the statutory backdrop against which the Board has developed the narrow requirement that striking employees must take reasonable 

precautions before or when they strike in order to forestall 

or address foreseeable, imminent, and aggravated injury to 

—————— 

other exceptions concern strikes for illegal objectives, strikes in breach 

of contract, and strikes in breach of other federal law. See S. Rep. No.

105, at 28. 
 

 

20 GLACIER NORTHWEST, INC. v. TEAMSTERS 

JACKSON, J., dissenting 

persons, premises, and equipment that might otherwise be

caused by their sudden cessation of work.

The Board first applied this “reasonable precautions” 

principle to rank-and-file employees in Marshall Car Wheel 

& Foundry Co., Inc., 107 N. L. R. B. 314, 315 (1953), enf.

denied on other grounds, 218 F. 2d 409 (CA5 1955). There, 

employees at a foundry walked off the job at a time when 

the foundry’s furnace was full of hot molten iron, threatening severe damage to the employer’s plant and equipment.

107 N. L. R. B., at 315. The Board concluded that the employees’ strike conduct was not protected by the NLRA, because the employees had a “duty to take reasonable precautions to protect the employer’s physical plant from such

imminent damage as for[e]seeably would result from their 

sudden cessation of work.” Ibid. 

The Board has also applied this principle in other similar 

cases. It determined, for example, that strikers who walked

out of a certain kind of chemical plant—a plant that handled “extremely hazardous” chemicals that were “a hazard 

not only to employees but also to individuals living in the 

vicinity”—without shutting down the equipment had engaged in unprotected conduct. General Chemical Corp., 290 

N. L. R. B. 76, 77, 83 (1988). Similarly, the Board held that 

the strike conduct of security guards whose walkout exposed a federal building’s occupants to “imminent” danger

was not protected by the NLRA. International Protective 

Servs., Inc., 339 N. L. R. B. 701, 703 (2003).

But the narrow duty that Marshall Car Wheel and its 

progeny impose does not—and cannot—displace the general rule that labor strikes are protected even when the

workers’ withdrawal of their labor inflicts economic harm 

on the employer. So the Board has also repeatedly held that

employees have no duty to prevent the loss of perishable 

goods caused by their sudden cessation of work.

In a leading case, employees at a raw poultry plant de-
 

 

Cite as: 598 U. S. ____ (2023) 21 

JACKSON, J., dissenting 

cided to walk out at 8 a.m. “because by that time all employees would have reported to work and [the employer] would 

be in full operation with its largest number of chickens on 

the line.” Lumbee Farms Co-op., 285 N. L. R. B. 497, 503 

(1987). The Board affirmed the ALJ’s reasoning that “[t]he

fact that the strike occurred during the workday when 

chickens were on the line and vulnerable to loss does not 

mean employees automatically lost protection under the

Act,” because “[s]trikers are not required under the Act to

institute the strike at a specific time of day.” Id., at 506. 

Indeed, it is “[n]orma[l]” for “planned employee strikes [to

be] timed to ensure the greatest impact on an employer.” 

Ibid. 

The Board has applied this same reasoning in cases involving, for example, cheese and milk. See Leprino Cheese 

Co., 170 N. L. R. B. 601, 605 (1968); Central Okla. Milk Producers Assn., 125 N. L. R. B. 419, 435 (1959). In those 

cases, the Board also explained that the reasonable-precautions principle is “limited to situations involving a danger

of ‘aggravated’ injury to persons or premises”—a danger

“[o]bviously” not posed by the loss of, for example, cheese. 

Leprino Cheese, 170 N. L. R. B., at 607 (emphasis added).

The Board has consistently reiterated that “[l]oss is not uncommon when a strike occurs.” Central Okla. Milk Producers, 125 N. L. R. B., at 435. 

In short, it is indisputable that workers have a statutory 

right to strike despite the fact that exercising that right

risks economic harm to employers. Congress has, in effect, 

drawn a line between those economic harms that are inherent in the act of peacefully walking off the job (which do not 

render the strike unprotected), and those that result from 

workers taking subsequent affirmative steps to seize the 

employer’s premises or engage in acts of violence (strike

conduct that is not protected by the NLRA). The Board has 

further recognized a narrow duty that arises if a sudden 
 

22 GLACIER NORTHWEST, INC. v. TEAMSTERS 

JACKSON, J., dissenting 

cessation of work risks foreseeable, imminent, and aggravated harm to persons, premises, or equipment. Beyond

this narrow reasonable-precautions requirement, however,

employees have no obligation to protect their employer’s 

economic interests when they exercise the right to withhold 

their labor. 

B 

Glacier does not allege that the cement truckdrivers committed acts of violence or seized its plant or property as part 

of the strike the Union orchestrated. Instead, the thrust of 

its complaint is that the Union was aware of “the perishable 

nature of batched concrete,” App. 9, and that the drivers’ 

walkout was intentionally timed so as to risk harm to that

product. See id., at 10 (alleging “sabotage, ruination and 

destruction of Glacier’s batched concrete”).

I agree with the majority that the risk of losing the

batched concrete alone would not be sufficient to divest the 

striking drivers of statutory protection. As Glacier 

acknowledges, wet concrete is a perishable good. Ibid. And 

the Board has repeatedly reaffirmed that the loss of such

perishable goods due to a mere work stoppage does not render a strike unprotected. 

There is also no duty to take reasonable precautions to

prevent this kind of economic loss, which—standing

alone—posed no risk to persons, premises, or equipment, let 

alone a risk of aggravated harm. While it seems that the 

drivers were in a position to save the batched concrete that

was inside their trucks when the strike was called (by, for

instance, continuing to deliver it to the intended customers), that is beside the point. Employees have a protected 

right to withhold their labor. And it would undercut that 

right if they could be held liable for the incidental loss of the

perishable goods (which includes concrete no less than raw 

poultry, cheese, or milk) that they tend to as part of their 
 

 

Cite as: 598 U. S. ____ (2023) 23 

JACKSON, J., dissenting 

job.7 

Where I disagree with the majority is the conclusion it 

draws from the fact that the batched concrete also risked 

harm to the drivers’ trucks, at least as alleged in Glacier’s

complaint. The majority repeatedly ties the loss of the concrete—in particular, the risk that it would harden in the 

trucks—to the alleged risk of harm to the delivery trucks

themselves.8 But, to me, the alleged risk of harm to Glacier’s trucks involves a relatively complex factual analysis 

under the Board’s reasonable-precautions principle.

Glacier alleges that, “[o]nce at rest, concrete begins hardening immediately, and depending on the mix can begin to 

set within 20 to 30 minutes.” Id., at 8. Its complaint also

asserts that “[i]f batched concrete remains in the revolving

drum of the ready-mix truck beyond its useful life span, the 

batched concrete is certain or substantially certain to 

—————— 7 JUSTICE ALITO, relying on the rule from NLRB v. Fansteel Metallurgical Corp., 306 U. S. 240 (1939), gleans more from the loss of concrete 

than either the majority or I do. He concludes that the NLRA’s right to 

strike does not protect the drivers’ alleged conduct because Glacier has 

alleged that the drivers purposefully caused the batched concrete to be 

destroyed. In my view, that approach fails to appreciate the distinction 

Fansteel drew between purposefully but peacefully stopping work (and 

the economic consequences that flow from that decision), which is protected, and taking subsequent, affirmative steps of violence or property 

seizure, which is unprotected. To be sure, Fansteel would have rendered 

the drivers’ actions here patently unprotected if they had taken the affirmative steps of stealing the trucks, slashing the trucks’ tires, or dumping out the concrete after they went on strike. But nothing like that is 

alleged in Glacier’s complaint. 8See, e.g., ante, at 8 (“[T]he Union executed the strike in a manner 

designed to compromise the safety of Glacier’s trucks and destroy its concrete”); ante, at 10 (“[The drivers] not only destroyed the concrete but 

also put Glacier’s trucks in harm’s way. This case therefore involves 

much more than ‘a work stoppage at a time when the loss of perishable 

products is foreseeable’ ”); ante, at 12 (“The Union’s actions not only resulted in the destruction of all the concrete Glacier had prepared that 

day; they also posed a risk of foreseeable, aggravated, and imminent 

harm to Glacier’s trucks”). 
 

 

24 GLACIER NORTHWEST, INC. v. TEAMSTERS 

JACKSON, J., dissenting 

harden in the revolving drum and cause significant damage 

to the concrete ready-mix truck.” Id., at 9. But Glacier’s 

own submissions in Washington state court suggest that 

the Union instructed the drivers to return their trucks to 

Glacier’s yard after the strike began and to keep the readymix trucks running. See id., at 34, 77. Glacier’s submissions also suggest that those precautions actually provided

the company’s managers and nonstriking employees with

sufficient time to decide how to address the situation to prevent any harm to the trucks. See id., at 13, 72, 77, 82–83. 

Was any risk of harm to the trucks here “imminent,”

given the allegation that the Union instructed the drivers

to keep the trucks running? Is the risk of concrete hardening in a delivery truck “aggravated,” in the way Marshall 

Car Wheel contemplates? Was returning the trucks to the 

employer’s premises and leaving them running a sufficient 

“reasonable” precaution, because it gave the employer sufficient time to address any risk of harm? Making the call 

about whether the NLRA protects the Union’s conduct 

raises these questions and others. Importantly, these kinds 

of questions not only involve making nuanced factual distinctions but also demonstrate that applying the Board’s 

reasonable-precautions precedents is, at bottom, a linedrawing exercise. Under circumstances like these, a court 

can confidently declare that a union’s conduct is not even 

arguably protected for Garmon purposes only where the allegations make out a clear Fansteel claim or where the alleged facts implicate a reasonable-precautions case that is

directly on point. Because neither is true here, the Court 

should have concluded that the Union’s conduct was at 

least arguably protected. 

Even if the Court’s task under Garmon were to apply the

Board’s reasonable-precautions principle to the allegations

of Glacier’s complaint and decide whether or not the Union 

engaged in unprotected conduct (to reiterate: that is not the

assignment, see Part III–A, supra), I cannot agree with the 
 

Cite as: 598 U. S. ____ (2023) 25 

JACKSON, J., dissenting 

majority’s conclusion that the risk to the trucks rendered

the drivers’ strike unprotected by the NLRA. Instead, I 

would have credited Glacier’s own account, and thus would 

have concluded that the Union took reasonable precautions

when it instructed the drivers to return the trucks and 

leave them running to avoid the concrete hardening imminently in the drums. The majority reaches the opposite conclusion by giving far too little weight to the allegation that

the drivers returned the trucks, and also by substantially

discounting the allegations that support the Union’s claim

that the drivers left their trucks and revolving drums running. See ante, at 11. 

Fortunately, the pending Board determination of what

actually happened in connection with this particular strike 

will establish—as a matter of fact and not mere allegation—what precautions (if any) the drivers actually took 

and what harm (if any) the Union’s conduct actually posed 

to Glacier’s trucks.9 But our different takes on these allegations only underscore the potential for variable outcomes 

when courts apply the Board’s fact-dependent principles to 

bare assertions. 

To the extent that the majority’s conclusion rests on the 

alleged fact that “by reporting for duty and pretending as if 

they would deliver the concrete, the drivers prompted the 

creation of the perishable product” that “put Glacier’s

trucks in harm’s way,” ante, at 10, I see nothing aggravated

or even untoward about that conduct. Glacier is a concretedelivery company whose drivers are responsible for delivering wet concrete, so it is unremarkable that the drivers 

struck at a time when there was concrete in the trucks. 

While selling perishable products may be risky business,

the perishable nature of Glacier’s concrete did not impose 

—————— 9For the same reason, the state court would not be bound by the majority’s recitation of the facts at this motion-to-dismiss stage in any future proceedings on this matter in state court. 
 

 

26 GLACIER NORTHWEST, INC. v. TEAMSTERS 

JACKSON, J., dissenting 

some obligation on the drivers to strike in the middle of the

night or before the next day’s jobs had started. To the contrary, it was entirely lawful for the drivers to start their 

workday per usual, and for the Union to time the strike to

put “maximum pressure on the employer at minimum economic cost to the union.” NLRB v. Insurance Agents, 361 

U. S. 477, 496 (1960); see also Lumbee Farms Co-op., 285 

N. L. R. B., at 506. 

Nor was the onus of protecting Glacier’s economic interests if a strike was called in the middle of the day on the

drivers—it was, instead, on Glacier, which could have taken 

any number of prophylactic, mitigating measures.10 What 

Glacier seeks to do here is to shift the duty of protecting an

employer’s property from damage or loss incident to a strike 

onto the striking workers, beyond what the Board has already permitted via the reasonable-precautions principle.

In my view, doing that places a significant burden on the 

employees’ exercise of their statutory right to strike, unjustifiably undermining Congress’s intent. Workers are not 

indentured servants, bound to continue laboring until any 

planned work stoppage would be as painless as possible for 

their master. They are employees whose collective and 

peaceful decision to withhold their labor is protected by the

NLRA even if economic injury results. 

* * * 

Today, the majority fails, in multiple respects, to heed

Congress’s intent with respect to the Board’s primary role 

in adjudicating labor disputes, despite ostensibly applying 

—————— 10For example, Glacier could have instituted a lockout, see American 

Ship Building Co. v. NLRB, 380 U. S. 300, 310 (1965), used nonstriking 

employees to deliver the batched concrete, or had temporary replacement

drivers lined up and ready to go. Glacier was on notice that a strike was 

possible because the Union was statutorily required to give 60-days advance notice of the proposed termination or modification of the collectivebargaining agreement, §158(d), and because negotiations had broken 

down. 
Cite as: 598 U. S. ____ (2023) 27 

JACKSON, J., dissenting 

Garmon, the bedrock case on that issue. The Court’s ruling 

is likely to cause considerable confusion among the lower 

courts about what Garmon requires. And any such confusion not only threatens to encroach upon the Board’s prerogatives, as Congress has assigned them, but also risks

erosion of the right to strike.

Yet, the posture of this case provides an opportunity to

mitigate the results of the majority’s errors. On remand, 

the state court should dismiss Glacier’s complaint without

prejudice or stay its proceedings in view of the General 

Counsel’s complaint. Meanwhile, the Board—which is not 

bound by the allegations in Glacier’s complaint when making its assessment, and is well equipped to make findings

of fact concerning the strike conduct at issue—should proceed to determine whether Glacier has interfered with 

strike conduct that is protected by the NLRA, as alleged by

the General Counsel.