Opinion of the Court
other allegations of the complaint, be thought to be $80 million payable to each of the four plaintiff States and the Commission.
North Carolina argues, however, that summary judgment in its favor is appropriate because it is clear that the Commission, and not the plaintiff States, provided $80 million to North Carolina—wherefore, as a matter of law, only the Commission can claim entitlement to $80 million, either as a measure of damages for breach of the Compact under Counts I and II of the bill of complaint, see Restatement §370, Comment a, and §373, or under the unjust enrichment, promissory estoppel, and money-had-and-received theories of recovery in Counts III, IV, and V, see, e.g., Restatement of Restitution §1, Comment a (1936). And, it contends, a stand-alone suit by the Commission is barred by sovereign immunity.
With regard to Counts I and II, at least, we disagree. The Commission’s claims under those Compact-related Counts are wholly derivative of the States’ claims. See Arizona v. California, supra, at 614. The Commission is “a legal entity separate and distinct from” the States that are parties to the Compact. Art. 4(M)(1), 99 Stat. 1877. Since it is not a party it has neither a contractual right to performance by the party States nor enforceable statutory rights under Article 5 of the Compact, see Bennett v. Spear, 520 U. S. 154, 162–163 (1997). The Compact does, however, authorize the Commission to “act or appear on behalf of any party [S]tate or [S]tates . . . as an intervenor or party in interest before . . . any court of law,” Art. 4(E)(10), 99 Stat. 1875, and it is obviously in this capacity that the Commission seeks to vindicate the plaintiff States’ statutory and contractual rights in Counts I and II. Its Count I and Count II claims therefore rise or fall with the claims of the States. While the Commission may not bring them in a stand-alone action under this Court’s original jurisdiction, see §1251(a), it may assert them in