What follows is an opinion from a United States Court of Appeals.
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Maria-Kelly F. YNIGUEZ; Jaime P. Gutierrez, Plaintiffs, v. STATE OF ARIZONA, Defendant-Appellee. Robert D. Parks; Arizonans for Official English, Applicants in intervention-Appellants. Maria-Kelly F. YNIGUEZ; Jaime P. Gutierrez, Plaintiffs-Appellees, v. Rose MOFFORD, individually and as Governor of the State of Arizona; Robert Corbin, individually and as Attorney General of the State of Arizona, Defendants-Appellants. Robert D. Parks; Arizonans for Official English, Applicants in intervention-Appellees.
Nos. 90-15546, 90-15581.
United States Court of Appeals, Ninth Circuit.
Argued and Submitted Dec. 14, 1990.
Decided July 19, 1991.
Robert K. Corbin, Atty. Gen., Anthony B. Ching, Sol. Gen., Paula S. Bickett, Asst. Atty. Gen., Phoenix, Ariz., for state appellants.
Robert J. Pohlman, Pohlman & Sanders, Phoenix, Ariz., for plaintiffs-appellees.
Barnaby W. Zall, Williams & Jensen, Washington, D.C., for the appellant, mov-ants & intervenors.
James F. Henderson, Gust, Rosenfeld & Henderson, Phoenix, Ariz., for the appellants, movants, intervenors.
Before TANG, FLETCHER and REINHARDT, Circuit Judges.
REINHARDT, Circuit Judge:
This case presents two novel questions concerning post-judgment intervention: first, whether the sponsors of a ballot initiative may intervene after judgment to appeal a decision holding the ballot initiative unconstitutional when the only defendant in the case chooses not to appeal; and second, whether the Attorney General, having argued for and won a dismissal of the suit against him in the district court, may intervene on appeal.
FACTUAL AND PROCEDURAL BACKGROUND
Arizonans for Official English (“AOE”) and its spokesman Robert D. Park campaigned for adoption by ballot initiative of an amendment to the Arizona Constitution entitled “English as the Official Language.” In the November 1988 general election, the Arizona voters approved the new constitutional provision. That new provision, Article XXVIII of the Arizona Constitution (“Article XXVIII”) provides in part:
English shall be the official language of the State of Arizona and all of its political subdivisions, that the Article is applicable to all branches of government and to all government officials and employees during the performance of government business, that the state and its political subdivisions shall take all reasonable steps to preserve, protect and enhance the role of English as the state’s official language, that the state and its political subdivisions ... shall act only in English....
Section Four of Article XXVIII states that “[a] person who resides in or does business in this State shall have standing to bring suit to enforce this Article in a court of record of the State. The Legislature may enact reasonable limitations on the time and manner of bringing suit under this subsection.” The Arizona legislature has not enacted any limitations on private lawsuits to enforce Article XXVIII.
Maria-Kelly Yniguez, an employee of the Arizona Department of Administration, ceased speaking Spanish while performing her official state duties immediately upon passage of Article XXVIII. She feared that under Article XXVIII she was vulnerable to discipline by her state employer if she were to continue to speak Spanish on the job. In November 1988 Yniguez sued (in a series of amended complaints) the State of Arizona, Governor Rose Mofford, Arizona Attorney General Robert Corbin, and Director of the Arizona Department of Administration Catherine Eden in federal district court. Yniguez sought an injunction against state enforcement of Article XXVIII and a declaration that it violates the first and fourteenth amendments of the United States Constitution.
The state defendants all moved for dismissal, arguing that the eleventh amendment barred Yniguez’s suit and that there was no live “case or controversy,” U.S. Const, art. Ill, between Yniguez and any of the defendants. All of the state defendants were represented by the Attorney General’s office. The district court then proceeded to issue a series of thoughtful and carefully reasoned rulings, most of which are not now before us.
On February 6, 1990, the district court dismissed all defendants from the suit except the Governor. The court held that the eleventh amendment bars suit against Arizona. The court further held that the Attorney General is an improper party under the doctrine of Ex Parte Young, 209 U.S. 123, 28 S.Ct. 441, 52 L.Ed. 714 (1908), because he has no authority to enforce Article XXVIII against Yniguez. Therefore, the court held that the eleventh amendment also bars Yniguez’s suit against the Attorney General. Although the district court found that Eden has authority to enforce Article XXVIII, she had not threatened to do so, and thus the court held that no case or controversy was ripe for adjudication as to her. The district court therefore dismissed Eden from the suit as well. Finally, the district court held that the Governor has the authority to enforce Article XXVIII against Yniguez and had sufficiently threatened to do so for Yniguez to sue her under Ex parte Young.
Having dismissed all the defendants except the Governor, the district court proceeded on the same date, February 6, 1990, to rule on the merits of Yniguez’s claim. The court held that Article XXVIII is facially unconstitutional under the first amendment. It therefore granted Yniguez declaratory relief, but denied injunctive relief because there was no enforcement action pending. Governor Mofford — who had publicly opposed the adoption of Article XXVIII during the 1988 election — immediately announced her decision not to appeal the district court’s opinion and order.
On February 16, 1990, AOE and its spokesperson Park moved to intervene post-judgment for the purpose of pursuing an appeal of the district court’s order. They sought to intervene both as of right and permissively under Fed.R.Civ.P. 24. During arguments before the district court and this court, the attorneys for the Attorney General’s office and for AOE and Park averred that AOE had inquired of the Attorney General at an early stage of the lawsuit whether he would vigorously defend the constitutionality of Article XXVIII, and that they had been assured that he would. Yniguez does not contend otherwise. On March 2,1990, the Attorney General sought to intervene for the purpose of prosecuting the appeal pursuant to 28 U.S.C. § 2403(b).
On April 3,1990, the district court denied both motions to intervene. 130 F.R.D. 410. Although the court found that AOE’s and Park’s motion was timely, it denied it on two grounds. First, the court held that the prospective intervenors did not satisfy the Article III requirement of injury-in-fact necessary for there to be a justiciable controversy. In addition, the court denied the motion to intervene as of right on the ground that AOE and Park did not have an adequate interest in the litigation under Fed.R.Civ.P. 24(a)(2). The district court stated that its decision on the merits would not bind the Arizona courts, and therefore that AOE’s and Park’s ability to enforce Article XXVIII was not impaired by the decision. The district court also denied the Attorney General’s motion to intervene under 28 U.S.C. § 2403(b). Section 2403(b) authorizes intervention by a state attorney general in actions “to which [the] State or any agency, officer, or employee thereof is not a party.” The district court noted that although the Governor had not appealed, she remained a party. Accordingly, the court concluded that section 2403(b) is not applicable. These timely appeals of the denial of the motions to intervene followed.
STANDARD OF REVIEW
We review de novo the denial of a motion to intervene. Waller v. Financial Corp. of America, 828 F.2d 579, 582 (9th Cir.1987). The district court’s determination of timeliness, however, is reviewed only for an abuse of discretion. County of Orange v. Air California, 799 F.2d 535, 537 (9th Cir.1986), cert. denied, 480 U.S. 946, 107 S.Ct. 1605, 94 L.Ed.2d 791 (1987).
DISCUSSION
I. AOE and Park
AOE and Park contend that they have a right to intervene on appeal under Fed.R.Civ.P. 24(a) (“Intervention of Right”). Rule 24 of the Federal Rules of Civil Procedure confers a right to intervene “[u]pon timely application” when:
the applicant claims an interest relating to the property or transaction which is the subject of the action and the applicant is so situated that the disposition of the action may as a practical matter impair or impede the applicant’s ability to protect that interest, unless the applicant's interest is adequately represented by existing parties.
Fed.R.Civ.P. 24(a)(2). In Sagebrush Rebellion, Inc. v. Watt, 713 F.2d 525 (9th Cir.1983), we interpreted Rule 24(a) to require the granting of a motion to intervene at the outset of litigation if four criteria are met: (1) timeliness; (2) an interest in the subject matter of the litigation; (3) absent intervention the party’s interest may be practically impaired; (4) other parties inadequately represent the intervenor. Id. at 527.
In order for an individual to intervene in ongoing litigation between other parties, he need only meet the Sagebrush Rebellion criteria. However, where no party appeals, the “case or controversy” requirement of Article III also qualifies an applicant’s right to intervene post-judgment. In Legal Aid Soc’y. of Alameda County v. Brennan, 608 F.2d 1319 (9th Cir.1979), cert. denied, 447 U.S. 921, 100 S.Ct. 3010, 65 L.Ed.2d 1112 (1980), we restated the rule that “post-judgment intervention for purposes of appeal may be appropriate if the intervenors ... meet traditional standing criteria.” Id. at 1328 (citations omitted). As the Supreme Court stated in Diamond v. Charles, 476 U.S. 54, 106 S.Ct. 1697, 90 L.Ed.2d 48 (1986), "[ajlthough intervenors are considered parties entitled, among other things, to seek review ... an intervenor’s right to continue a suit in the absence of the party on whose side intervention was permitted is contingent upon a showing by the intervenor that he fulfills the requirements of Art. III.” Id. at 68, 106 S.Ct. at 1706 (citation omitted; emphasis added). This requirement assures the jurisdictional prerequisite of a live “case or controversy.”
As we explained in Brennan, once the party defendants have “acquiesced in the judgment against them,” as the Governor did here, applicants “must demonstrate such a stake in the outcome of an appeal that a live Article III case or controversy remains for appellate resolution.” Brennan, 608 F.2d at 1328 n. 6. Therefore, an interest strong enough to permit intervention with parties at the onset of an action under Rule 24(a) is not necessarily a sufficient basis for intervention after judgment for the purpose of pursuing an appeal which all parties have abandoned. In Brennan we cited a commentator to illustrate this jurisdictional limitation:
A distinction between standing to intervene and to appeal makes particular sense when the “case or controversy” limitation on the federal judicial power is recalled. Adding C to the litigation between A and B may pose no problems under Article III of the Constitution, but permitting C to be the sole adversary of B on appeal, when his interest in the case may be only in its value as precedent, certainly does give difficulty since there is no real controversy between A and C.
Shapiro, Some Thoughts on Intervention Before Courts, Agencies, and Arbitrators, 81 Harv.L.Rev. 721, 753-54 (1968) (cited with approval in Brennan, 608 F.2d at 1328 n. 9). Hence, before assessing whether AOE and Park meet the Sagebrush Rebellion criteria, we must first decide whether permitting them to intervene on appeal would be consistent with the requirements of Article III.
A. Article III Standing
AOE and Park can meet the Article III “standing criteria by alleging a threat of particularized injury from the order they seek to reverse that would be avoided or redressed if their appeal succeeds.” Brennan, 608 F.2d at 1328. AOE and Park contend, as they did in the district court, that they satisfy this test because, as the sponsors of Article XXVIII, they will be injured by its nullification. The district court held that this “abstract” interest is insufficiently concrete to satisfy Article III. Yniguez urges us to adopt the district court’s reasoning, citing Diamond v. Charles.
In Diamond, a private physician had intervened at the trial level in an action to enjoin enforcement of an Illinois statute restricting the performance of abortions. After the Court of Appeals affirmed a permanent injunction against the enforcement of the statute, the state decided not to appeal. The private physician, claiming that he had an interest in seeing Illinois’ laws enforced, attempted to appeal to the United States Supreme Court. The Court held that he lacked standing because although he had “an interest” he lacked a “direct stake [] in the abortion process.” 476 U.S. at 66, 106 S.Ct. at 1706.
From Diamond, Yniguez would have us conclude that a mere “philosophical interest in the outcome of litigation is insufficient to confer a right to appeal.” While we agree with this statement, we reject the suggestion that AOE and Park are mere “ ‘concerned bystanders,’ who will use [the appeal] simply as a ‘vehicle for the vindication of value interests.’ ” Diamond, 476 U.S. at 62, 106 S.Ct. at 1703 (quoting Sierra Club v. Morton, 405 U.S. 727, 740, 92 S.Ct. 1361, 1368, 31 L.Ed.2d 636 (1972); United States v. SCRAP, 412 U.S. 669, 687, 93 S.Ct. 2405, 2415, 37 L.Ed.2d 254 (1973)). We find that AOE’s and Park’s interest in Article XXVIII is qualitatively distinct from the physician’s interest in the Illinois abortion law at issue in Diamond. Unlike the physician, neither AOE nor Park is a mere “private citizen.” 476 U.S. at 64, 106 S.Ct. at 1704. As the principal sponsors of Article XXVIII, their relationship to Article XXVIII is closely analogous to the relationship of a state legislature to a state statute. It is therefore useful to consider the law of legislative standing.
In Karcher v. May, 484 U.S. 72, 108 S.Ct. 388, 98 L.Ed.2d 327 (1987), the Supreme Court held that state legislators who intervened in their official capacities to defend a lawsuit challenging the constitutionality of a statute that had been enacted over the Governor’s veto did not have standing once they were out of office. But in arriving at that decision, the Court clearly indicated that jurisdiction had been proper in the district court and the court of appeals so long as the legislators held office, notwithstanding the fact that the Attorney General had declined to defend the suit. See id. at 72-73, 108 S.Ct. at 390-91. As Justice White pointed out in his concurrence in the judgment, by allowing the legislators to intervene to defend the suit when the state executive did not wish to assert the statute’s constitutionality, the Court “acknowledged that the New Jersey Legislature and its authorized representative have the authority to defend the constitutionality of a statute attacked in federal court.” Id. at 84-85, 108 S.Ct. at 396. Furthermore, as the Court recognized over a half century ago, state legislators claiming that their votes “have been overridden and virtually held for naught” by an Executive decision have a sufficient stake in the outcome under Article III to vindicate their interests in federal court. Coleman v. Miller, 307 U.S. 433, 438, 59 S.Ct. 972, 975, 83 L.Ed. 1385 (1939) (holding that 20 state senators who voted against ratification of a federal constitutional amendment had standing to challenge the state lieutenant governor’s legal authority to cast the deciding vote in favor of the amendment).
It is therefore clear that were Article XXVIII a statute rather than a ballot initiative, the Arizona legislature would have standing to defend its constitutionality. AOE argues that as the principal sponsor of the initiative, it stands in an analogous position to a state legislature. We agree. The official sponsors of a ballot initiative have a strong interest in the vitality of a provision of the state constitution which they proposed and for which they vigorously campaigned. The district court’s decision striking down Article XXVIII essentially nullified the considerable efforts AOE made to have the initiative placed on the ballot and to obtain its passage. Cf. Coleman v. Miller, supra, p. 439, 59 S.Ct. p. 975.
Arizona law recognizes the ballot initiative sponsor’s heightened interest in the measure by giving the sponsor official rights and duties distinct from those of the voters at large. See, e.g., Ariz.Rev.Stat. Ann. § 19-111 (“person or organization intending to propose a law or constitutional amendment by petition” must file an application with the secretary of state); § 19-122 (if the secretary of state rejects a petition for a ballot initiative, he must provide the sponsor with a written statement of reasons for doing so); § 19-124 (sponsor may submit an argument in favor of the initiative at the time the application is filed).
Moreover, as appears to be true in this case, the government may be less than enthusiastic about the enforcement of a measure adopted by ballot initiative; for better or worse, the people generally resort to a ballot initiative precisely because they do not believe that the ordinary processes of representative government are sufficiently sensitive to the popular will with respect to a particular subject. While the people may not always be able to count on their elected representatives to support fully and fairly a provision enacted by ballot initiative, they can invariably depend on its sponsors to do so.
Finally, it is worth noting that there is a virtual per se rule that the sponsors of a ballot initiative have a sufficient interest in the subject matter of litigation concerning that initiative to intervene pursuant to Fed.R.Civ.P. 24(a). See infra, part I.B.2. While the interest required to intervene under the Rule is not identical to the interest required for standing under Article III, there are substantial similarities between the two. For the reasons we have already given, the added interest necessary to confer Article III standing — a particularized injury that distinguishes AOE from “concerned bystanders,” Diamond, 476 U.S. at 62, 106 S.Ct. at 1703 — is present here.
We conclude that AOE, as the sponsor of Article XXVIII, has standing to pursue the instant appeal.
Quite apart from our consideration of AOE’s status as the sponsor of the initiative, we hold that Park, as an individual, has standing under the traditional Article III standards applicable to all private citizens. Yniguez argues that because the district court’s decision has not “injured” Park in a tangible way, the Article III standing requirements are not met. However, when we consider Park’s standing as an individual the relevant question is not: has Yniguez injured Park? Rather, because Yniguez brought this case seeking declaratory and injunctive relief, the crucial question for determining whether there is an Article III case or controversy is instead: was there a more than speculative threat that Park was about to bring an action to enforce Article XXVIII against Yniguez? If so, then there was a sufficiently ripe case or controversy between Yniguez and Park to justify an action for declaratory relief. See Babbitt v. United Farm Workers Nat’l Union, 442 U.S. 289, 298, 99 S.Ct. 2301, 2308, 60 L.Ed.2d 895 (1979) (federal declaratory relief is available “[wjhen the plaintiff has alleged an intention to engage in a course of conduct arguably affected with a constitutional interest, but proscribed by a [provision of state law], and there exists a credible threat of prosecution thereunder....”); Ripplinger v. Collins, 868 F.2d 1043, 1047 (9th Cir.1989) (because of the risk of self-censorship, a reasonable fear of prosecution for the exercise of first amendment rights was shown where plaintiff alleged that sheriff had conducted preliminary investigation of his activities and others had been indicted for similar activities); Polykoff v. Collins, 816 F.2d 1326, 1331 (9th Cir.1987) (declaratory relief available because of the chilling effect of obscenity statute).
It is plain from the face of Article XXVIII, that Park could have sued Yniguez to enforce it. We must now determine whether there was a more than speculative threat that he would do so. As we have indicated, this is a question of ripeness.
Generally the ripeness question on appeal in a declaratory judgment case focuses on whether there was a ripe case or controversy when the suit was initiated. See Ripplinger, 868 F.2d at 1047 (discussing reasonableness of the plaintiffs fear of prosecution “at the time of filing [of the] lawsuit”). Because Park was not a party to the action below, the district court made no specific finding as to whether he had threatened to enforce Article XXVIII against Yniguez. However, the Attorney General has attested that Park and AOE did not intervene at an early stage in the proceedings only because they had been expressly assured by the Attorney General that he would vigorously represent their interests. Thus, we may treat AOE’s and Park’s assertion of their interests in the litigation to the Attorney General as an expression, at the time of the initiation of the proceedings, of their intention to see Article XXVIII enforced against Yniguez. At the outset of litigation, Yniguez therefore could have had a reasonable expectation that Park (and possibly AOE as well) would bring an enforcement action against her. As a result, the United Farm Workers Nat’l Union requirements are met.
We therefore hold that AOE and Park have standing to appeal.
B. The Sagebrush Rebellion Criteria
We next consider the four criteria under Fed.R.Civ.P. 24(a) in turn.
1. Timeliness
The district court found that AOE’s and Park’s motion to intervene was timely. The court applied the general rule that a post-judgment motion to intervene is timely if filed within the time allowed for the filing of an appeal. However, the district court also considered whether the motion was timely in light of the fact that AOE and Park did not move to intervene until after the judgment. The district court noted that AOE’s and Park’s complaints about the adequacy of the Attorney General’s defense of Article XXVIII indicated that they should have intervened during the litigation. The court also noted that AOE and Park did not realize the supposed inadequacy of the Attorney General’s defense until very late in the proceedings. The court further acknowledged that an early motion to intervene could have been futile because of the Attorney General’s opposition to intervention and his assurances to AOE and Park that he would vigorously defend Article XXVIII. After considering all of these factors, the district court concluded that the motion was timely.
There is no contention that the time that elapsed between the judgment and AOE’s and Park’s motion was excessive. The only question here is whether AOE and Park should have attempted to intervene before the final judgment in the court below. Although, as the district court noted, the most prudent course for AOE and Park to have followed would have been to attempt to intervene as soon as they had doubts about the Attorney General’s representation, we cannot fault them for relying on that official’s assurance that he would defend Article XXVIII fully. Having received that assurance, AOE and Park were not required to monitor the litigation closely to see if the government was asserting a position which, if accepted, could prejudice their interests. Moreover, given the Attorney General’s stated view that he would fully defend Article XXVIII, we doubt whether an early motion by AOE and Park to intervene would have been granted, especially if it had been opposed by the Attorney General. Thus, we cannot say that the district court abused its discretion by finding that their motion to intervene was timely.
2. Interest in the Subject Matter of the Litigation
There appears to be a virtual per se rule that the sponsors of a ballot initiative have a sufficient interest in the subject matter of the litigation to intervene pursuant to Fed.R.Civ.P. 24(a). As we stated in Washington State Bldg. & Constr. Trades Council v. Spellman, 684 F.2d 627, 630 (9th Cir.1982), cert. denied, 461 U.S. 913, 103 S.Ct. 1891, 77 L.Ed.2d 282 (1983), because “[r]ule 24 traditionally has received a liberal construction ... the public interest group that sponsored the initiative [is] entitled to intervention as a matter of right under Rule 24(a).” Accord Sagebrush Rebellion, 713 F.2d at 527-28. Moreover, because the Article III standing requirements are more stringent than those for intervention under rule 24(a), see supra, p. 731-32, our determination that AOE and Park have standing under Article III compels the conclusion that they have an adequate interest under the rule.
3. Practical Impairment Absent Intervention
Yniguez argues that AOE’s and Park’s interests are not impaired by the district court’s decision because they retain the right to sue in state court to enforce Article XXVIII. Yniguez correctly notes that the district court’s decision is not res judi-cata with respect to AOE and Park. As the Supreme Court has stated, “[i]t is a principle of general application in anglo-American jurisprudence that one is not bound by a judgment in personam in a litigation in which he is not designated as a party or to which he has not been made a party by service of process.” Martin v. Wilks, 490 U.S. 755, 109 S.Ct. 2180, 2184, 104 L.Ed.2d 835 (1989) (quoting Hansberry v. Lee, 311 U.S. 32, 40, 61 S.Ct. 115, 117, 85 L.Ed. 22 (1940)). However, this principle is not dispositive, because the question here is whether the district court’s decision will result in practical impairment of the interests of AOE and Park, not whether the decision itself binds them.
Yniguez next contends that the district court’s judgment is no impediment to AOE and Park because it is not a binding precedent on the state courts. All parties agree that it is not binding in the sense that the courts of Arizona are free to place a different interpretation on Article XXVIII and thereby render it constitutional. That is, there is no dispute that the Arizona courts are the definitive expositors of Arizona state law. However, Yniguez’ argument goes one step further. She contends in her brief that even assuming that the district court correctly understood the meaning of Article XXVIII, its decision that Article XXVIII is unconstitutional as a matter of federal law has no stare decisis effect in the Arizona state courts. The district court also took this narrow view of the effect of its decision. See supra, p. 730 & n. 1. AOE and Park contend that the view advanced by Yniguez in her brief, and accepted by the district court, overstates the power of state courts to ignore decisions of the lower federal courts.
The view that decisions of the lower federal courts on questions of federal law do not bind the state courts has gained considerable acceptance in the academic literature. It has also been expressed by some state courts, although others have expressed the opposite view. And while the Supreme Court has never squarely faced the question, several individual justices have stated that principles of federalism require that the state courts be treated as coordinate and coequal with the lower federal courts on matters of federal law.
Despite the authorities that take the view that the state courts are free to ignore decisions of the lower federal courts on federal questions, we have serious doubts as to the wisdom of this view. Having chosen to create the lower federal courts, Congress may have intended that just as state courts have the final word on questions of state law, the federal courts ought to have the final word on questions of federal law. The contrary view could lead to considerable friction between the state and federal courts as well as duplica-tive litigation. Furthermore, the sparse authority on the subject appears to be concerned largely with the stare decisis effect of federal district court decisions on subsequent state court actions, rather than the effect of decisions of the federal courts of appeals; there may be valid reasons not to bind the state courts to a decision of a single federal district judge — which is not even binding on the same judge in a subsequent action — that are inapplicable to decisions of the federal courts of appeals. Finally, if decisions of the federal courts of appeals invalidating state laws carry no authority, it would be difficult to comprehend why for so many years a right of appeal to the Supreme Court was provided in all cases in which federal circuit courts held state statutes unconstitutional. See 28 U.S.C.A. § 1254(2) (West 1979). In any event, we may assume without deciding that an unappealed judgment of the district court would have no precedential weight in the Arizona courts, for even under this assumption, we find that the interests of AOE and Park are practically impaired by the decision.
There is no dispute that the declaration that Article XXVIII is facially invalid binds Governor Mofford and her successors in any actions against Ms. Yniguez. This fact alone suggests that the interests of AOE and Park have been practically impaired. Moreover, there is at least some uncertainty as to whether it would also bind the Governor of Arizona in enforcement suits against defendants other than Ms. Yniguez. Compare H.L. v. Matheson, 450 U.S. 398, 406, 101 S.Ct. 1164, 1169, 67 L.Ed.2d 388 (1981) (stating categorically that an unappealed ruling of a federal district court is binding on a state party), with United States v. Mendoza, 464 U.S. 154, 104 S.Ct. 568, 78 L.Ed.2d 379 (1984) (holding that non-mutual offensive collateral es-toppel may not be applied against the federal government). As a result, Arizona’s Governor may hesitate to take any steps to implement Article XXVIII. Indeed, the Attorney General has represented to this court that in light of the district court’s decision, he believes that any enforcement of Article XXVIII would be of questionable legality, and we cannot fault him for his willingness to abide by a federal court’s declaration that the provision is unconstitutional. Yet Article XXVIII places an affirmative duty on that official to “take all reasonable steps to preserve, protect and enhance the role of English as the state’s official language.” The district court’s decision casts a cloud over the state’s power to enforce Article XXVIII. While it may have left AOE’s and Park’s right to sue intact, a right to bring a private enforcement action is not a complete substitute for executive enforcement and implementation. Hence, as a practical matter, the district court’s ruling substantially weakened Article XXVIII, and thereby impaired the interest of AOE and Park.
Furthermore, even if we assume that the district court’s ruling has no binding effect on the Arizona courts, we cannot wholly overlook the fact that jurisprudential concerns might cause those courts to find the reasoning of the district court more persuasive than they might otherwise find a similar argument to be, and that they might choose to accept the district court’s reasoning to avoid confusion, lack of finality, and disrespect for law. See Commonwealth v. Negri, 419 Pa. 117, 121-22, 213 A.2d 670, 672 (1965). In any event, the district court’s opinion will have impaired AOE’s and Park’s interests in the vitality of Article XXVIII.
4. Inadequacy of Representation by Other Parties
Having decided not to appeal the district court’s decision on the merits, the Governor inadequately represents the interests of AOE and Park. Moreover, as we hold below, the Attorney General is estopped from re-entering this litigation as a party. See infra, p. 738. Thus, absent an appeal by AOE and Park, no party will be able to assert Article XXVIII’s constitutionality. Because no representation constitutes inadequate representation, the fourth Sagebrush Rebellion criterion is met.
Furthermore, even if the government were a party to this appeal, that would not ensure adequate representation of the interests of AOE and Park. The Attorney General has issued an opinion narrowly construing Article XXVIII. In his view, the English-only requirement applies solely to official acts of the Arizona government, and does not prohibit the use of languages other than English by state personnel such as Yniguez. The district court rejected the Attorney General’s proffered construction because it is not binding on the Arizona courts and because, in the view of the district court, it contradicts the plain language of Article XXVIII. By contrast with the Attorney General, AOE and Park agree with the district court that Article XXVIII should be construed broadly, although they disagree with the court that the provision so construed is unconstitutional. In any event, at this stage in the proceedings it is clear that the Attorney General would not represent the views of AOE and Park adequately.
II. The Attorney General’s Intervention Motion
Attorney General Corbin claims a right to intervene under Fed.R.Civ.P. 24(a) and 28 U.S.C. § 2403. Because we hold that there is an Article III “case or controversy” between Yniguez (on the one hand) and AOE and Park (on the other), we need not address the question whether the Attorney General would have standing to appeal under Article III if no other party were willing and able to appeal. Thus, we turn directly to his claims under Rule 24(a) and section 2403.
A. Rule 24(a)
We note initially that the Attorney General did not contend in the district court that his putative right to intervene was located in Rule 24(a). The sole basis for his intervention motion in the court below was section 2403. Thus, we have serious doubts whether his claim under Rule 24(a) is properly before us. Even if it is, however, we find that having argued in the district court that he should not be a party, the Attorney General is estopped from now arguing that he should be.
As we explained in Russell v. Rolfs, 893 F.2d 1033, 1037 (9th Cir.1990), “ ‘[t]he doctrine of judicial estoppel, sometimes referred to as the doctrine of preclusion of inconsistent positions, is invoked to prevent a party from changing its position over the course of judicial proceedings when such positional changes have

Question: What is the most frequently cited federal rule of civil procedure in the headnotes to this case? Answer with a number.

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