FOR PUBLICATION

UNITED STATES COURT OF APPEALS

FOR THE NINTH CIRCUIT

POTRERO HILLS LANDFILL, INC.; 

BLT ENTERPRISES OF SACRAMENTO,

INC.; BRENTWOOD DISPOSAL

SERVICE, INC.; CONCORD DISPOSAL

SERVICE, INC.; CONTRA COSTA

WASTE SERVICE, INC.; DISCOVERY

BAY DISPOSAL, INC.; OAKLEY

DISPOSAL SERVICE, INC.; PITTSBURG

DISPOSAL AND DEBRIS BOX SERVICE,

INC.; RIO VISTA SANITATION

SERVICE, INC.; WASTE CONNECTIONS,

INC.; WASTE CONNECTIONS OF No. 10-15229

CALIFORNIA, INC., DBA El Dorado D.C. No. Disposal Service; TRASHPROS,

 2:09-cv-02514- LLC; WEST COAST RECYCLING AND JAM-JFM TRANSFER, INC.,

Plaintiffs-Appellants, OPINION

v.

COUNTY OF SOLANO,

Defendant-Appellee,

SIERRA CLUB; NORTHERN

CALIFORNIA RECYCLING

ASSOCIATION; SPRAWLDEF, AKA

Sustainability, Parks, Recycling

and Wildlife Defense Fund,

Defendants-IntervenorsAppellees. 

Appeal from the United States District Court

for the Eastern District of California

John A. Mendez, District Judge, Presiding

17295
Argued and Submitted

April 14, 2011—Pasadena, California

Filed September 13, 2011

Before: Stephen Reinhardt, Michael Daly Hawkins, and

Ronald M. Gould, Circuit Judges.

Opinion by Judge Hawkins

17296 POTRERO HILLS LANDFILL v. COUNTY OF SOLANO
COUNSEL

James B. Slaughter, Beveridge and Diamond, Washington,

D.C., and Lily N. Chinn, Beveridge and Diamond, San Francisco, California, for the plaintiffs-appellants.

James W. Laughlin, Deputy County Counsel, Fairfield, California, for the defendant-appellee.

Robert S. Perlmutter, Shute, Mihaly & Weinberger, San Francisco, California, for defendant-intervenor-appellee Sierra

Club.

John Douglas Moore, Henn, Etzel & Moore, Inc., Oakland,

California, for defendant-intervenor-appellee Northern California Recycling Association.

Kelly T. Smith, The Smith Firm, Sacramento, California, for

defendant-intervenor-appellee Sustainability, Parks, Recycling and Wildlife Legal Defense Fund.

OPINION

HAWKINS, Senior Circuit Judge:

Potrero Hills Landfill (“Potrero Hills”), a privately owned

solid waste and recycling business in Solano County, California (“the County”), and twenty-two related businesses appeal

the dismissal on Younger1 abstention grounds of their 42

U.S.C. § 1983 action for declaratory and injunctive relief

1

See Younger v. Harris, 401 U.S. 37 (1971). 

POTRERO HILLS LANDFILL v. COUNTY OF SOLANO 17299
challenging the constitutionality of a voter-enacted county

ordinance restricting the import of out-of-county solid waste

into Solano County—an ordinance that the County itself

believes to be unconstitutional and refuses to enforce. We

hold that Younger abstention does not apply here. Although

private mandamus actions seeking to compel the County to

enforce the challenged ordinance were ongoing in state court

at the time this case was filed, those state proceedings were

brought by private interest groups and therefore did not implicate the state’s unique interest in protecting its vital executive

function of law enforcement; nor did they implicate the state’s

unique interests in protecting its vital judicial or legislative

functions. Put differently, a federal court’s exercise of jurisdiction over Potrero Hills’ claim would not interfere with the

state’s exercise of a basic state function and would not offend

the principles of comity and federalism that Younger abstention was designed to uphold. Accordingly, we vacate and

remand. As part of the remand, we ask the district court to

consider whether Pullman,

2

 rather than Younger, abstention

might be appropriate.

FACTS AND PROCEDURAL HISTORY

I. Background

In 1984, voters in Solano County (“the County”) enacted a

ballot initiative, titled “Initiative Ordinance to Protect Solano

County’s Environment from Excessive Importation of Solid

Waste” (“Measure E”), capping the annual amount of solid

waste that may be imported into Solano County at 95,000 tons.3

2

See R.R. Comm’n of Tex. v. Pullman Co., 312 U.S. 496 (1941). 

3Section 2 of Measure E provides in relevant part: 

The County of Solano shall not create a policy, adopt a resolution

or ordinance, enter into a contract or in any manner allow for the

importation of any solid waste . . . which originated or was collected outside the territorial limits of Solano County which will

bring the cumulative total amount of such imported solid waste

in excess of 95,000 tons per year. 

17300 POTRERO HILLS LANDFILL v. COUNTY OF SOLANO
The measure contained no restrictions on the disposal of solid

waste generated within the County.

Although the County initially complied with Measure E by

including annual waste import limits in its Solid Waste Management Plan, it stopped doing so in 1992, in reliance on a

legal opinion issued by the Solano County Counsel concluding that Measure E was likely unconstitutional, in light of two

recent Supreme Court decisions striking down similar local

waste import restrictions as violative of the dormant Commerce Clause.4

 The Legislative Counsel of California reached

the same conclusion in its own legal opinion on the measure.

Shortly thereafter, the County approved permit revision applications from each of the two major solid waste facilities

located within the County, one of which was Potrero Hills,

allowing disposal of increased quantities of solid waste.

Although the permits did not explicitly allow importation of

more than 95,000 tons of out-of-County solid waste, it authorized a quantity substantially greater than locally generated

amounts, thus implicitly permitting the two facilities to violate Measure E. 

As a result, Potrero Hills became one of the three largest

landfills servicing the San Francisco Bay Area and today

4The Supreme Court struck down as unconstitutional in violation of the

dormant Commerce Clause an Alabama statute imposing a waste disposal

fee only on hazardous wastes generated outside the State and disposed of

at a commercial facility within the State, but not on hazardous wastes generated within the State. Chem. Waste Mgmt., Inc. v. Hunt, 504 U.S. 334,

336-37 (1992). The Court also struck down on dormant Commerce Clause

grounds a Michigan statute prohibiting private landfill operators from

accepting solid waste originating outside the county in which their facilities are located. Fort Gratiot Sanitary Landfill, Inc. v. Mich. Dep’t of Natural Res., 504 U.S. 353, 361 (1992). The Court held that a county’s

restrictions on interstate commerce violate the dormant Commerce Clause

just as much as does a state’s. Id. (“[A] State (or one of its political subdivisions) may not avoid the strictures of the Commerce Clause by curtailing the movement of articles of commerce through subdivisions of the

State, rather than through the State itself.”). 

POTRERO HILLS LANDFILL v. COUNTY OF SOLANO 17301
receives some 600,000 tons of solid waste annually from

jurisdictions outside Solano County, comprising two-thirds of

its total waste intake. Projected to reach full capacity by 2011,

it sought permission from the County in 2002 to expand its

landfill from 320 to 580 acres, which would provide an additional 61.6 million cubic feet (43 million tons) of new capacity (“Expansion Project”). The Solano County Board of

Supervisors approved the Expansion Project and certified the

project’s Final Environmental Impact Report (“EIR”).

Several environmental groups opposing the Expansion

Project, including Intervenor Northern California Recycling

Association (“NCRA”), brought suit in Solano County Superior Court challenging the sufficiency of the EIR pursuant to

the California Environmental Quality Act. A revised EIR was

produced and approved but was subject to a second suit by

environmental groups, including Intervenor Sustainability,

Parks, Recycling, and Wildlife Legal Defense Fund

(“Wildlife Fund”), who raised Measure E as an additional bar

to approval of the Expansion Project. A third EIR was produced and once again approved. 

II. State Mandamus Petitions

Following final approval of Potrero Hills’ Expansion Project, NCRA, Wildlife Fund, and a third environmental group,

the Sierra Club, each filed a mandamus action in Solano

County Superior Court, all seeking generalized injunctive

relief requiring the County to enforce Measure E, two of them

naming Potrero Hills as a real party in interest and seeking to

overturn the County’s approval of the landfill Expansion Project. The three proceedings were consolidated for briefing and

hearing on the merits. 

III. Federal Action

A few weeks after the last state mandamus action was filed,

Potrero Hills and twenty-two other plaintiffs involved in the

17302 POTRERO HILLS LANDFILL v. COUNTY OF SOLANO
solid waste and recycling business in either Northern California, Nevada, or Oregon, filed this single-cause action under

42 U.S.C. § 1983 seeking a declaration that Measure E is

unconstitutional in violation of the Commerce Clause and an

injunction blocking its enforcement. The three state court

petitioners intervened (“Intervenors”) and moved to dismiss

under Federal Rules of Civil Procedure 12(b)(6) and 12(b)(1),

or in the alternative to abstain from deciding the case under

Younger and Pullman. Potrero Hills opposed the motions to

dismiss and was joined by the County in requesting resolution

in federal court, as well as by the State of California, which

filed an amicus brief.5 Citing the state’s important interests in

“enforcement of Measure E, a local ordinance enacted by California voters,” and in “enforcement of its local solid waste

ordinance,” the district court invoked Younger abstention and

dismissed the suit without reaching Intervenor’s alternative

arguments for dismissal.6

STANDARD OF REVIEW

We review de novo the district court’s decision to abstain

5The State of California’s particular interest in this suit arises from

Potrero Hills’ role in a 2008 antitrust consent decree negotiated by the

California Attorney General and the U.S. Department of Justice. Concerned by the potential anti-competitive effects of a proposed merger

between the second and third largest waste hauling and disposal companies in the United States, Allied Waste, Inc. and Republic Services, Inc.,

respectively, who combined owned all three of the major solid waste landfills in the Bay Area (Keller Canyon in Contra Costa County, Vasco Road

in Alameda County, and Potrero Hills in Solano County), the California

AG and U.S. Department of Justice entered into a consent decree allowing

Allied and Republic to merge only upon the condition that Republic divest

Potrero Hills (which was subsequently purchased in April 2009 by Waste

Connections, Inc., another major competitor). 

6The events that transpired subsequent to the district court’s dismissal

are not relevant to our review of the district court’s decision to abstain

under Younger, which we undertake in light of the facts and circumstances

existing at the time the federal action was filed. See Gilbertson v. Albright,

381 F.3d 965, 969 n.4 (9th Cir. 2004) (en banc). 

POTRERO HILLS LANDFILL v. COUNTY OF SOLANO 17303
under the Younger doctrine. Green v. City of Tucson, 255 F.3d

1086, 1093 (9th Cir. 2001) (en banc), overruled in part on

other grounds by Gilbertson v. Albright, 381 F.3d 965, 976-

78 (9th Cir. 2004) (en banc).

DISCUSSION

The issue before us is not the constitutionality of Measure

E but rather only whether the district court properly dismissed

the case based on Younger abstention, a doctrine that forbids

federal courts from unduly interfering with pending state

court proceedings that implicate “important state interests.”

Middlesex Cnty. Ethics Comm. v. Garden State Bar Ass’n,

457 U.S. 423, 432 (1982). The district court determined that

the ongoing state mandamus proceedings implicate the state’s

important interests in (1) enforcing a local ordinance enacted

by California voters and (2) enforcing a local solid waste ordinance, and that the remaining Younger requirements are also

satisfied. Although we agree that a state’s interest in having

its executive branch enforce such measures is sufficiently

important for Younger purposes, we conclude that a private

litigant’s interest in seeing such measures enforced, which is

all we have here, does not implicate the principles of comity

and federalism with which Younger and its progeny are concerned.

I. Basic Younger Principles

[1] Although Younger itself held that, absent extraordinary

circumstances, a federal court may not interfere with a pending state criminal prosecution, 401 U.S. at 54, the Supreme

Court has extended Younger abstention to the civil context on

numerous occasions. In Middlesex County Ethics Committee

v. Garden State Bar Association, 457 U.S. 423 (1982), the

Supreme Court laid out a three-part test for determining when

to apply Younger to a civil proceeding, holding that abstention

is required so long as the state proceedings: (1) are ongoing;

(2) implicate “important state interests”; and (3) provide an

17304 POTRERO HILLS LANDFILL v. COUNTY OF SOLANO
adequate opportunity to raise federal questions. 457 U.S. at

432. To these three threshold requirements, we recently articulated an implied fourth requirement that (4) the federal court

action would “ ‘enjoin the proceeding, or have the practical

effect of doing so.’ ” AmerisourceBergen Corp. v. Roden, 495

F.3d 1143, 1148-49 (9th Cir. 2007) (quoting Gilbertson, 381

F.3d at 978).

[2] The case now before us is an unprecedented candidate

for Younger abstention and provides us a much-needed opportunity to clarify the scope of what constitutes an “important

state interest.” Though recognizing “important state interests”

in a wide variety of civil proceedings, neither we nor the

Supreme Court has held Younger to apply generally to ordinary civil litigation. See Middlesex, 457 U.S. at 432 (extending Younger to noncriminal judicial proceedings only “when

important state interests are involved”); Miofsky v. Superior

Court of the State of Cal., 703 F.2d 332, 338 & n.9 (9th Cir.

1983) (declining to extend Younger to encompass “conventional civil litigation”). To the contrary, abstention remains an

extraordinary and narrow exception to the general rule that

federal courts “ ‘have no more right to decline the exercise of

jurisdiction which is given, than to usurp that which is not

given.’ ” New Orleans Pub. Serv., Inc. v. Council of the City

of New Orleans, 491 U.S. 350, 358 (1989) (“NOPSI”) (quoting Cohens v. Va., 6 Wheat. 264, 404 (1821)); see Cnty. of

Allegheny v. Frank Mashuda Co., 360 U.S. 185, 188-89

(1959); Gilbertson, 381 F.3d at 969 n.2. Consequently, each

time we are asked to extend Younger to a new type of state

civil proceeding, we must determine whether federal adjudication would offend the doctrine’s animating principles, foremost of which is

the notion of ‘comity,’ that is, a proper respect for

state functions, a recognition of the fact that the

entire country is made up of a Union of separate

state governments, and a continuance of the belief

that the National Government will fare best if the

POTRERO HILLS LANDFILL v. COUNTY OF SOLANO 17305
States and their institutions are left free to perform

their separate functions in their separate ways . . . .

[T]he concept [represents] a system in which there is

sensitivity to the legitimate interests of both State

and National Governments, and in which the

National Government, anxious though it may be to

vindicate and protect federal rights and federal interests, always endeavors to do so in ways that will not

unduly interfere with the legitimate activities of the

States.

Younger, 401 U.S. at 44 (emphases added); see also Pennzoil

Co. v. Texaco, Inc., 481 U.S. 1, 11 (1987).

The key to determining whether comity concerns are implicated in an ongoing state proceeding — and thus whether the

second Younger requirement is met — is to ask whether federal court adjudication would interfere with the state’s ability

to carry out its basic executive, judicial, or legislative functions. Unless interests “vital to the operation of state government” are at stake, federal district courts must fulfill their

“unflagging obligation” to exercise the jurisdiction given

them. Miofsky, 703 F.2d at 337, 338 (internal quotation marks

omitted); accord Polykoff; IAS, Inc. v. Collins, 816 F.2d 1326,

1332 (9th Cir. 1987).

II. Whether This Case Implicates Vital State 

Functions

Here, the first and third threshold Younger requirements

appear easily satisfied. Potrero Hills concedes it was not prevented from raising its constitutional argument in state court,

and state judicial proceedings were indisputably “ongoing” at

the time Potrero Hills filed this federal action.7 We conclude,

7Potrero Hills does not dispute that the state mandamus proceedings

were already underway when it filed this § 1983 action but nonetheless

insists that Younger abstention applies only to ongoing proceedings initi17306 POTRERO HILLS LANDFILL v. COUNTY OF SOLANO
however, that the state mandamus actions do not implicate

any important state interests vital to the operation of state

government. Because the second requirement is not satisfied,

dismissal based on Younger abstention was not required here.8

A. No Vital Executive Interests

1. The State is Not in an Enforcement Posture

[3] The Younger doctrine recognizes that a state’s ability

to enforce its laws “ ‘against socially harmful conduct that the

State believes in good faith to be punishable under its laws

and Constitution’ ” is a “basic state function” with which federal courts should not interfere. Miofsky, 703 F.2d at 336

(quoting Younger, 401 U.S. at 51-52). Where the state is in an

ated by the state. This argument confuses the inquiries under prongs one

and two, as our case law clearly demonstrates that the first Younger prong

may be satisfied even when the ongoing state proceeding involves only

private litigants. See, e.g., Pennzoil, 481 U.S. at 12-14; Juidice v. Vail, 430

U.S. 327, 335-36 (1977); AmerisourceBergen, 495 F.3d at 1149 (ultimately finding abstention improper due to lack of important state interests

but finding the first element satisfied in a private contract dispute). The

significance of the lack of a state-initiated enforcement proceeding is more

appropriately considered under the second Younger prong. 

8We need not discuss the fourth component of Younger abstention, for

only if all three threshold Middlesex requirements are satisfied do we then

consider whether the federal action would unduly interfere with the state

proceeding “ ‘in a way that Younger disapproves.’ ” AmerisourceBergen,

495 F.3d at 1149 (quoting Gilbertson, 381 F.3d at 978)). If the state

actions are not the type of proceeding to which Younger applies, then the

preclusive effect of any federal court ruling on the parallel proceeding by

virtue of res judicata or collateral estoppel is irrelevant for abstention purposes. See id. at 1151. Where concerns of comity are absent, “the ‘mere

potential for conflict in the results of adjudications’ is not the kind of

‘interference’ that merits federal court abstention. Rather, the possibility

of a race to judgment is inherent in a system of dual sovereigns.” Green,

255 F.3d at 1097 (quoting Colo. River Water Conservation Dist. v. United

States, 424 U.S. 800, 816 (1976)); accord AmerisourceBergen, 495 F.3d

at 1151. 

POTRERO HILLS LANDFILL v. COUNTY OF SOLANO 17307
enforcement posture in the state proceedings, the “important

state interest” requirement is easily satisfied, as the state’s

vital interest in carrying out its executive functions is presumptively at stake.9

See Fresh Int’l Corp. v. Agric. Labor

Relations Bd., 805 F.2d 1353, 1360 n.8 (9th Cir. 1986) (“The

state’s interest in a civil proceeding is readily apparent when

the state through one of its agencies acts essentially as a prosecutor.” (internal quotation marks and alterations omitted));

see also Trainor v. Hernandez, 431 U.S. 434, 444 (1977)

(emphasizing that the state brought suit in its sovereign capacity). Thus, when the state seeks to enforce a law of significant

state importance through judicial or quasi-judicial action, we

have found abstention necessary to protect the state’s unique

interest in exercising its basic executive functions in a wide

range of civil contexts. See, e.g., Ohio Civil Rights Comm’n

v. Dayton Christian Schs., Inc., 477 U.S. 619, 628 (1986)

(recognizing state’s important interest in enforcing its

employment anti-discrimination laws through administrative

proceedings); Moore v. Sims, 442 U.S. 415, 435 (1979) (same

for enforcing child custody laws); Trainor, 431 U.S. at 444

(enforcing state welfare scheme); San Jose Silicon Valley

9This presumption is overcome only under extraordinary circumstances,

such as where (1) the “state proceeding is motivated by a desire to harass

or is conducted in bad faith,” Huffman v. Pursue, Ltd., 420 U.S. 592, 611

(1975); see Younger, 401 U.S. at 47-49; (2) the challenged provision is

“ ‘flagrantly and patently violative of express constitutional prohibitions in

every clause, sentence and paragraph, and in whatever manner and against

whomever an effort might be made to apply it,’ ” Younger, 401 U.S. at 53-

54 (quoting Watson v. Buck, 313 U.S. 387, 402 (1941)); (3) the state

forum is “incompetent by reason of bias,” Hirsh v. Justices of the Supreme

Court of the State of Cal., 67 F.3d 708, 713 (9th Cir. 1995) (citing Gibson

v. Berryhill, 411 U.S. 564, 577-79 (1973)); or (4) when federal preemption

of a state law is “readily apparent,” Bud Antle, Inc. v. Barbosa, 45 F.3d

1261, 1272-73 (9th Cir. 1994) (explaining that when state law is “clearly

preempt[ed]” by federal law, “there is ‘no principle of comity or of “our

federalism’ ” that abstention would serve” (quoting Fresh Int’l, 805 F.2d

at 1361 n.11)); accord Champion Int’l Corp. v. Brown, 731 F.2d 1406,

1408-09 (9th Cir. 1984) (finding no significant state interest at stake where

state law was clearly preempted by ERISA). 

17308 POTRERO HILLS LANDFILL v. COUNTY OF SOLANO
Chamber of Commerce Political Action Comm. v. City of San

Jose, 546 F.3d 1087, 1094 (9th Cir. 2008) (enforcing local

election regulations); Gilbertson, 381 F.3d at 983 (enforcing

land-surveying licensing provisions); Baffert v. Cal. Horse

Racing Bd., 332 F.3d 613, 618 (9th Cir. 2003) (enforcing

horse-racing licensing procedures); Woodfeathers, Inc. v.

Washington Cnty., Or., 180 F.3d 1017, 1021 (9th Cir. 1999)

(enforcing solid waste disposal and recycling ordinance); San

Remo Hotel v. City and Cnty. of S.F., 145 F.3d 1095, 1104

(9th Cir. 1998) (enforcing land-use and zoning ordinances);

World Famous Drinking Emporium, Inc. v. City of Tempe,

820 F.2d 1079, 1083 (9th Cir. 1987) (enforcing nuisance

laws); Worldwide Church of God, Inc. v. State of Cal., 623

F.2d 613, 616 (9th Cir. 1980) (per curiam) (investigating

charitable trust fraud pursuant to state Attorney General’s

supervisory authority).

[4] Here, the district court identified two state interests it

thought sufficiently “important” to warrant abstention: first,

the state’s interest in enforcing its ballot initiatives, and second, the state’s interest in enforcing its local solid waste ordinances. However, as we explained above, it is not the bare

subject matter of the underlying state law that we test to determine whether the state proceeding implicates an “important

state interest” for Younger purposes. Were that so, then any

ordinary civil litigation between private parties requiring the

interpretation of state law would pass Younger muster. Rather,

the content of state laws becomes “important” for Younger

purposes only when coupled with the state executive’s interest

in enforcing such laws. Had Solano County enforced Measure

E against Potrero Hills and denied it the revised Use Permit,

no doubt the second Younger requirement would be satisfied.

See Woodfeathers, 180 F.3d at 1021 (“[T]he County’s

enforcement of its solid waste ordinance implicates important

state interests for the purpose of Younger v. Harris.” (emphasis added)). But here, “the [County] simply was not in any

type of enforcement posture against [Potrero Hills] at the time

[Potrero Hills] filed the federal action attacking the constituPOTRERO HILLS LANDFILL v. COUNTY OF SOLANO 17309
tionality of the legislative enactment.” Exec. Arts Studio, Inc.

v. City of Grand Rapids, 391 F.3d 783, 791 (6th Cir. 2004).

Accordingly, the state’s vital executive functions would not

be unduly hampered by a federal court’s adjudication of

Potrero Hills’ claim.

2. Private Citizens Lack Executive Powers

[5] Intervenors nonetheless assert that the state mandamus

actions, though initiated by private citizen groups rather than

by the state, qualify equally as “enforcement proceedings” for

Younger purposes. We find no support in the law for this

argument. The California Constitution reserves to the people

certain legislative powers, see Cal. Const. art. II, §§ 8-11; id.

art. IV, § 1, and the California Supreme Court is currently

considering whether the official proponents of initiative measures possess legal interests in upholding the constitutionality

of such measures when the executive officials vested with the

authority to do so refuse to exercise their authority. See Perry

v. Schwarzenegger, 628 F.3d 1191, 1193 (9th Cir. 2011);

Perry v. Brown, No.S189476 (Cal. Feb. 16, 2011) (granting

our request for certification). But Intervenors do not claim to

be the official proponents of Measure E, and private citizens

as a general matter lack executive authority to enforce state

laws, whether enacted by initiative or by the legislature. See,

e.g., Cal. Const. art. V, § 1 (“The supreme executive power of

this State is vested in the Governor.”). Private parties who are

aggrieved by the Executive’s failure to enforce a legislative

initiative or any other state law may be able to bring a mandamus action against the Executive in state court, but such

actions are neither sovereign in nature nor the exercise of the

executive authority of the state. Intervenors cite no authority

that instructs us to treat their mandamus actions as the equivalent of a state-initiated enforcement proceeding.

[6] At the time Potrero Hills filed this suit, it was not the

subject of any past or pending state-initiated enforcement proceeding; rather, Intervenors’ state mandamus actions made it

17310 POTRERO HILLS LANDFILL v. COUNTY OF SOLANO
the subject merely of prospective enforcement, where Younger does not apply. See Wooley v. Maynard, 430 U.S. 705,

711-12 (1977) (no Younger bar to federal injunctive relief in

the face of threatened repeated prospective state prosecution);

Steffel v. Thompson, 415 U.S. 452, 462 (1974) (no Younger

bar to federal declaratory relief when state proceedings are

not pending but only threatened); Wiener v. Cnty. of San

Diego, 23 F.3d 263, 267 (9th Cir. 1994); Exec. Arts Studio,

391 F.3d at 791-92. Where a federal plaintiff seeks relief not

from past state actions but merely from prospective enforcement of state law, federal court adjudication would not interfere with the state’s basic executive functions in a way

Younger disapproves. See Wooley, 430 U.S. at 709-11; Wiener, 23 F.3d at 267. While a state’s executive interest in

enforcing a local waste management ordinance would no

doubt qualify as abstention-worthy, private citizens generally

lack executive authority, and thus their efforts to enforce a

local waste management ordinance do not implicate the comity and federalism concerns that justify a federal court’s

extraordinary act of abstaining from hearing a case over

which it has jurisdiction. To hold otherwise would threaten to

“permit the exception to consume the rule.” Miofsky, 703 F.2d

332.

B. No Other Vital State Functions Implicated

Although no vital executive state functions are at stake,

Intervenors urge us to recognize two additional comity concerns and to affirm the district court’s decision to abstain

based on (1) the state judiciary’s interest in adjudicating federal constitutional claims and enforcing ballot initiatives, and

(2) the sovereign voters’ interest in exercising their right to

legislate. Although the state’s important interest in protecting

its executive functions is by no means its only abstentionworthy one, Intervenors fail to identify how federal court

adjudication of this suit would unduly interfere with the

state’s ability to perform its vital judicial or legislative functions.

POTRERO HILLS LANDFILL v. COUNTY OF SOLANO 17311
1. No Vital Judicial Interests

[7] To establish a vital interest in the state’s judicial functions, an abstention proponent must assert more than a state’s

generic interest in the resolution of an individual case or in

the enforcement of a single state court judgment. See Champion Int’l, 731 F.2d at 1408. Likewise, a state’s interest in a

universal judicial value such as “prompt resolution of cases”

is not cognizable for purposes of Younger abstention. See

AmerisourceBergen, 495 F.3d at 1150. Rather, the interest at

stake must go to “the core of the administration of a State’s

judicial system,” Juidice v. Vail, 430 U.S. 327, 335 (1977),

and its importance must be “ ‘measured by considering its significance broadly,’ ” AmerisourceBergen, 495 F.3d at 1150

(quoting Baffert, 332 F.3d at 618). For example, in both Juidice and Pennzoil, the federal plaintiffs brought challenges to

the very processes by which the state sought to compel compliance with the judgments of its courts, implicating the

state’s “wholesale interest in preserving its procedure for

posting an appeal bond” or in enforcing the orders and judgments of its courts through the contempt process. AmerisourceBergen, 495 F.3d at 1150; see Pennzoil, 481 U.S. at 12-14;

Juidice, 430 U.S. at 335-36 & n.12. Under such circumstances, “[n]ot only would federal injunctions . . . interfere

with the execution of state judgments, but they would do so

on grounds that challenge the very process by which those

judgments were obtained.” Pennzoil, 481 U.S. at 14 (emphasis added); see Polykoff, 816 F.2d at 1333.

Intervenors identify no comparable interest here in the state

judiciary’s vital functions, asserting instead only general judicial interests, such as the California state judiciary’s interest

in “providing a forum competent to vindicate any constitutional objections” to state laws. Equally unavailing is their

assertion of the state’s “important interest” in having its

courts issue writs of mandate to enforce voter initiatives.

Though it may be a “duty of the courts to jealously guard [the

initiative] right of the people” under California law, Bldg.

17312 POTRERO HILLS LANDFILL v. COUNTY OF SOLANO
Indus. Ass’n of S. Cal. v. City of Camarillo, 718 P.2d 68, 74

(Cal. 1986), the same can be said for a state court’s duty to

defend the federal Constitution, see Zwickler v. Koota, 389

U.S. 241, 248 (1967) (explaining that a federal court’s duty

“to give due respect to a suitor’s choice of a federal forum for

the hearing and decision of his federal constitutional claims”

cannot be avoided “merely because state courts also have the

solemn responsibility, equally with the federal courts, to

guard, enforce, and protect every right granted or secured by

the constitution of the United States” (internal quotation

marks and alterations omitted)). This type of generalized

interest does not fall within the scope of vital interests central

to the state courts’ functions recognized under Younger. See

NOPSI, 491 U.S. at 372-73; Polykoff, 816 F.2d at 1333

(abstention unwarranted where state action brought by county

attorney seeks only declaratory judgment on the same federal

issue as that involved in the federal action).

[8] To assert a vital state interest concerning the state judiciary, Intervenors must do more than assert a general interest

in the grant and enforcement of this writ of mandamus.

Potrero Hills’ suit challenges neither the authority of state

courts to issue such writs nor processes for their enforcement

once issued, and thus Intervenors have failed to establish that

a federal court’s adjudication of this case would unduly interfere with the state’s vital interest in “protecting ‘the authority

of [the state’s] judicial system, so that its orders and judgments are not rendered nugatory.’ ” Pennzoil, 481 U.S. at 14

n.12 (quoting Juidice, 430 U.S. at 336 n.12).

2. No Vital Legislative Interests

Finally, Intervenors assert Younger abstention’s concern for

comity should also recognize an important state interest in

protecting the state’s initiative process and the sovereign powers of Solano County voters. See Cal. Const. art. IV, § 1

(reserving to the people of California “the powers of initiative

and referendum”); Cal. Elec. Code § 9122 (“If a majority of

POTRERO HILLS LANDFILL v. COUNTY OF SOLANO 17313
the voters voting on a proposed ordinance vote in its favor,

the ordinance shall become a valid and binding ordinance of

the county.”). Although we are unaware of any cases where

Younger abstention has been found appropriate based on the

state’s important interest in protecting its legislative, as

opposed to executive or judicial, functions,10 we do not rule

out the possibility that the Younger doctrine’s principles could

be extended to recognize such important state interests,

should they in fact be implicated. See Mervynne v. Acker, 189

Cal. App. 2d 558, 563 (1961) (describing the exercise of initiative and referendum as “one of the most precious rights of

our democratic process”); cf. NOPSI, 491 U.S. at 372

(explaining that the Court is “as concerned . . . to preserve the

integrity of a unitary and still-to-be-completed legislative process as [it is] . . . to preserve the integrity of judicial proceedings”).

[9] Nonetheless, the power of voters to legislate through

the initiative process simply is not implicated here. This case

does not, for example, challenge the right of voters to initiate

legislation or the processes by which ballot initiatives become

law. And as noted earlier, Intervenors do not claim to be the

official proponents of Measure E; even assuming that under

certain circumstances such official proponents possess interests under state law in defending the validity of the initiatives

they sponsor, Intervenors assert no such interests here. This

case therefore does not implicate a state’s central legislative

functions any more than does a suit challenging the constitutionality of a state law passed by the legislature. See NOPSI,

491 U.S. at 372 (“As a challenge to completed legislative

action, NOPSI’s suit . . . is, insofar as our policies of federal

10Although Intervenors cite San Jose Silicon Valley, 546 F.3d at 1094,

for the proposition that enforcement of voter-enacted initiatives is an “important state interest,” the asserted state interest there was, again, the executive interest in enforcing “regulation of local elections.” That the

particular measure the city sought to enforce was enacted by ballot initiative was not central to the finding of an important state interest. 

17314 POTRERO HILLS LANDFILL v. COUNTY OF SOLANO
comity are concerned, no different in substance from a facial

challenge to an allegedly unconstitutional statute or zoning

ordinance—which we would assuredly not require to be

brought in state courts.”).

C. No Additional Comity Concerns

[10] Finally, that Solano County itself opposed abstention

and sought federal adjudication of Potrero Hills’ claim further

allays any concerns of offending comity. Abstention is not a

jurisdictional doctrine but rather a prudential one, allowing a

federal court to refuse to abstain where the state defendant

consents to federal jurisdiction. Although the Ninth Circuit

has not always deferred to a city’s request for federal adjudication, see, e.g., San Remo Hotel, 145 F.3d at 1104 (abstaining despite joint stipulation of the parties to stay state

proceedings pending resolution of the federal action), a state’s

voluntary submission to a federal forum eliminates the comity

and federalism concerns animating the Younger doctrine, and

the federal court need not “force the case back into the State’s

own system.” Ohio Bureau of Emp’t Servs. v. Hodory, 431

U.S. 471, 480 (1977) (“Younger principles . . . do not require

this Court to refuse Ohio the immediate adjudication it

seeks.”); see also Dayton Christian Schs., 477 U.S. at 626 (“A

state may of course voluntarily submit to federal jurisdiction

even though it might have had a tenable claim for [Younger]

abstention.”); Brown v. Hotel and Rest. Emps. and Bartenders

Int’l Union Local 54, 468 U.S. 491, 500 n.9 (1984); Kleenwell

Biohazard Waste & Gen. Ecology Consultants, Inc. v. Nelson,

48 F.3d 391, 394 (9th Cir. 1995). Here, not only were no

important state interests of the kind recognized by Younger at

stake, but the County—and the State of California, as amicus

—expressly asked the federal court to exercise its jurisdiction

to resolve this solitary question of federal constitutionality.

Under these circumstances, we find Younger abstention particularly unwarranted.

11

11Because we hold that the second element of Younger is not satisfied,

we need not consider Potrero Hills’ additional argument that abstention

denied federal plaintiffs not party to the state action their day in court. 

POTRERO HILLS LANDFILL v. COUNTY OF SOLANO 17315
III. Pullman Abstention

Intervenors alternatively urge us to determine that the district court should have abstained under Pullman.

12 See Pullman, 312 U.S. at 500-01. Though the various abstention

doctrines “are not rigid pigeonholes into which federal courts

must try to fit cases,” Pennzoil, 481 U.S. at 11 n.9, Pullman

abstention serves somewhat different objectives from Younger

and may be appropriate even when Younger is not.

Pullman generally is available only where three conditions

are satisfied: “(1) the federal plaintiff’s complaint requires

resolution of a sensitive question of federal constitutional law;

(2) the constitutional question could be mooted or narrowed

by a definitive ruling on the state law issues; and (3) the possibly determinative issue of state law is unclear.” Spoklie v.

Mont., 411 F.3d 1051, 1055 (9th Cir. 2005) (citing San Remo

Hotel, 145 F.3d at 1104); see also Smelt v. Cnty. of Orange,

447 F.3d 673, 679 (9th Cir. 2006). 

[11] Thus, whereas Younger abstention aims to avoid interference with a state’s vital functions, Pullman defers to state

court interpretations of state law, not only out of concern for

comity, but also to avoid “ ‘premature constitutional adjudication’ ” that would arise from “interpreting state law without

the benefit of an authoritative construction by state courts.”

Gilbertson, 381 F.3d at 971 n.6 (internal quotation marks

omitted); see also Pennzoil, 481 U.S. at 11 (observing that

“[w]hen federal courts interpret state statutes in a way that

raises constitutional questions, ‘a constitutional determination

is predicated on a reading of the statute that is not binding on

state courts and may be discredited at any time—thus essen12Even if we were to agree with the Intervenors that Pullman abstention

was warranted, we would not be able to affirm the district court’s dismissal on that basis but rather would be required to reverse and remand

with instructions to enter a stay under Pullman pending resolution of the

state law issues in state court. See San Remo Hotel, 145 F.3d at 1105 n.6.

17316 POTRERO HILLS LANDFILL v. COUNTY OF SOLANO
tially rendering the federal-court decision advisory and the litigation underlying it meaningless’ ” (quoting Moore, 442 U.S.

at 428)).

Certification of state law questions to California’s highest

court serves the same function, allowing federal courts to

avoid erroneously “deciding state-law questions antecedent to

federal constitutional issues.” Arizonans for Official English

v. Ariz., 520 U.S. 43, 75 (1997); accord Doyle v. City of Medford, 565 F.3d 536, 543-44 (9th Cir. 2006) (seeking certification of a state law question in a “Pullman-type abstention”

situation); cf. Cal. R. Ct. 8.548(b)(2), (f)(5).

Unlike Younger, which requires dismissal of the federal

action where all four conditions are met, Pullman is a discretionary doctrine that flows from the court’s equity powers.

See Baggett v. Bullitt, 377 U.S. 360, 375 (1964) (“ ‘[Pullman

abstention] is not an automatic rule applied whenever a federal court is faced with a doubtful issue of state law; it rather

involves a discretionary exercise of a court’s equity powers.”); accord Smelt, 447 F.3d at 678 (reviewing decision to

abstain under Pullman under a modified abuse of discretion

standard). But because the court below did not reach Intervenors’ Pullman argument, we have no exercise of discretion to

review.

[12] Here, the absence of a definitive state court interpretation of Measure E could raise Pullman concerns, particularly

because Intervenors urge an interpretation of Measure E

applying the waste-import restrictions only to other California

counties but not to other states.13 That said, however, where

13Even assuming the interpretation urged by Intervenors is a permissible

one under California rules of construction, such an interpretation might

not obviate the Commerce Clause question, though it would admittedly

change the contours of the inquiry. Cf. Fort Gratiot, 504 U.S. at 355; BFI

Med. Waste Sys. v. Whatcom Cnty., 983 F.2d 911 (9th Cir. 1992); Harper

v. Pub. Serv. Comm’n of W. Va., 396 F.3d 348 (4th Cir. 2005); but see On

POTRERO HILLS LANDFILL v. COUNTY OF SOLANO 17317
there is “no apparent saving construction” on the face of the

state law, abstention is unwarranted. Bd. of Airport Comm’rs

of City of L.A. v. Jews for Jesus, Inc., 482 U.S. 569, 575

(1987); see also Wisc. v. Constantineau, 400 U.S. 433, 439

(1971). Federal courts are not required to send a case to the

state court if doing so would simply “impose expense and

long delay upon the litigants without hope of its bearing

fruit,” Zwickler, 389 U.S. at 251; to the contrary, under such

circumstances, “it is the duty of a federal court to decide the

federal question when presented to it,” id. Rather than consider Pullman abstention de novo, we instead remand for the

district court to exercise its discretionary powers and determine in the first instance whether Pullman abstention is

appropriate under the circumstances presented.

CONCLUSION

Mindful that a federal court’s obligation to exercise its

jurisdiction is “ ‘particularly weighty’ ” when the federal

plaintiffs before it seek relief under 42 U.S.C. § 1983 for violation of their civil rights, Miofsky, 703 F.2d at 338 (quoting

Tovar v. Billmeyer, 609 F.2d 1291, 1293 (9th Cir. 1980)), we

decline to expand the “extraordinary and narrow exception”

created by Younger and its progeny to the circumstances presented here, id. (quoting Frank Mashuda, 360 U.S. at 188).

Because the state mandamus actions brought by private interest groups did not involve any uniquely state interests in protecting the state’s vital executive, judicial, or legislative

functions, Younger abstention was not available and did not

excuse the district court from its duty to adjudicate this federal constitutional claim. We therefore vacate and remand for

the Green Apartments LLC v. City of Tacoma, 241 F.3d 1235, 1241-42

(9th Cir. 2001) (municipal ordinance requiring all waste generated within

the city to be deposited at the city’s public disposal area did not implicate

Commerce Clause concerns where plaintiff alleged only intrastate burdens). 

17318 POTRERO HILLS LANDFILL v. COUNTY OF SOLANO
the district court to consider Intervenors’ alternative grounds

for dismissal, including Pullman abstention, in the first

instance.

VACATED and REMANDED. Each party shall bear its

own costs on appeal.

POTRERO HILLS LANDFILL v. COUNTY OF SOLANO 17319