601 STEWART, J., concurring III The Court's readiness in Texas v. Florida to accept the interpleader analogy is understandable in the context of the then state of the law governing multiple taxation of intangibles. Before 1931 it had been taken as settled that, because the question of domicile was purely one of state law, it "must in many cases be impossible to have a single controlling decision upon the question," unless all interested parties could by chance or voluntary appearance be brought before a single forum. Baker v. Baker, Eccles & Co., 242 U. S. 394, 405. But when this Court held in 1931 that shares of stock and other intangible property could constitutionally "be subjected to a death transfer tax by one state only," that being the State of the decedent's domicile, First National Bank v. Maine, 284 U. S. 312, 328-330, it seemed implicit that there must be some means of protecting that right in a federal forum. The obvious next question was under what federal-court procedures conflicting state claims of domicile were to be resolved." The somewhat unexpected answer came in Worcester County Trust Co. v. Riley, 302 U. S. 292, which held that, at least for the ordinary estate, there was no means of forcing unwilling States to litigate the question of domicile, and the consequent right to tax the estate's intangibles, in a federal district court. In that case the estate of a decedent attempted to sue the taxing officials of two different States under the recently enacted Federal Interpleader Statute, 28 U. S. C. § 1335, to obtain a single, binding determination of the decedent's domicile at the time of his death. Despite the broad language of the First National Bank case, the Court held that "[n]either the Fourteenth Amendment nor the full faith and credit clause requires uniformity in the decisions of the courts 8 See Chafee, Federal Interpleader Since the Act of 1936, 49 Yale L. J. 377, 383-393 (1940), and authorities collected, id., at 383 n. 17; Nash, And Again Multiple Taxation?, 26 Geo. L. J. 288, 297 (1938). STEWART, J., Concurring 437 U.S. of different states as to the place of domicil, where the exertion of state power is dependent upon domicil within its boundaries." 302 U. S., at 299. After thus making clear that the imposition of multiple estate taxes on the basis of inconsistent adjudications of domicile presented no federal constitutional question, the opinion of the Court went on to foreclose recourse to the federal interpleader jurisdiction. Federal interpleader is based on diversity-of-citizenship jurisdiction, see State Farm Fire & Casualty Co. v. Tashire, 386 U. S. 523, 530-531, and a federal question is ordinarily not required.❞ But because the state tax officials were not acting unconstitutionally in attempting to impose taxes on the basis of valid state-court judgments, the Court held that the interpleader action was in substance a suit against the States themselves, and therefore barred by the Eleventh Amendment. See Ex parte Young, 209 U. S. 123.10 "There was no doubt that the dispute was in fact ideally suited to resolution by means of federal interpleader. Professor Chafee, upon whose work the Federal Interpleader Statute was largely based, believed that conflicting state claims of domicile presented a situation in which interpleader was "badly needed." Chafee, supra, n. 8, at 379. It is, he observed, "highly unfair for both state governments to tell the taxpayer, 'You have to pay only one tax,' and then make him pay twice." Id., at 384. He pointed out that the paradox of inconsistent adjudications of a theoretically single domicile is one created by our federal system of government: "In a nation with a unified government, the situation in which estates of decedents are here left remediless would be impossible. Either only one agency would impose death taxes; or else a single court of review would determine domicile as between two local taxing agencies. . . . Somewhere within that federal system we should be able to find remedies for the frictions which that system creates." Id., at 388. I believe such a remedy is now available. See n. 10, infra. 10 I think this holding has been substantially undercut by subsequent developments. In Edelman v. Jordan, 415 U. S. 651, the Court expressed an understanding of the Eleventh Amendment quite different from that manifested in Worcester County Trust Co. v. Riley, 302 U. S. 292. Thus it would appear that an estate confronted with multiple tax claims by two or more States could now bring an interpleader action in a federal 601 STEWART, J., concurring When the identical type of dispute was placed before this Court two years later in Texas v. Florida, the Court was thus understandably persuaded to view the complaint as presenting a question of domicile resolvable by a suit in the nature of interpleader to determine which State could alone impose the death tax. But the issue of the decedent's domicile in that case was merely a coincidental premise to the real basis of the dispute among the States-the risk that the claims of the competing States would exceed the net value of the estate, and that "the state lawfully entitled to collect the tax" would find itself unable to do so.12 As the opinion in Texas v. Florida made clear, insofar as the rights of the estate were concerned, each of the four States was "lawfully entitled" to collect the tax: "[T]wo or more states may each constitutionally assess death taxes on a decedent's intangibles upon a judicial determination that the district court seeking declaratory and injunctive relief against the tax officials of each State. I do not believe that the Tax Injunction Act, 28 U. S. C. § 1341, would preclude such a suit, if it were clear that the taxing States would not afford the estate a "plain, speedy and efficient remedy" for its claim that it should not be subjected to multiple taxes, e. g., by recognizing an earlier determination of domicile by a sister State. 11 At least one commentator so viewed the case when it was pending before the Court: "Texas v. Florida may become the wedge to open the door slammed in Worcester County Trust Co. v. Riley. It is so hard to believe that the Court will persist in its refusal to aid the states in the difficulty, one seizes on the slightest possibility to hope that there may yet come a solution." Nash, supra n. 8, at 314. 12 At oral argument on Texas' original motion for leave to file a bill of complaint in that case "the Court indicated that there was no justiciable controversy unless the assets of the estate were insufficient to pay the tax claims of all four of the states." Tweed & Sargent, Death and Taxes are Certain-But What of Domicile, 53 Harv. L. Rev. 68, 75 (1939). This first complaint was dismissed without prejudice. Texas v. New York, 300 U. S. 642. It was upon Texas' amended complaint, plainly alleging "on information and belief" that the assets were insufficient to meet all claims, that the Court took jurisdiction in Texas v. Florida. See also Massachusetts v. Missouri, 308 U. S. 1, 15. STEWART, J., concurring . 437 U.S. decedent was domiciled within it . . . ." 306 U. S., at 410. And a few months later the Court elaborated on this doctrine when it denied a motion to file a complaint in Massachusetts v. Missouri, 308 U. S. 1. There the Court made clear that both States were equally entitled to impose a tax so long as there was no risk that the estate would be depleted: "Missouri, in claiming a right to recover taxes from the respondent trustees, or in taking proceedings for collection, is not injuring Massachusetts. By the allegations, the property held in Missouri is amply sufficient to answer the claims of both States and recovery by either does not impair the exercise of any right the other may have." Id., at 15. Thus, even after Texas v. Florida, there was still no forum in which an estate confronted with conflicting tax claims could obtain a single, binding adjudication of domicile. So long as it was able to pay each State's claim, it was required to pay taxes to any State that obtained a judgment of domicile in its own courts. And, so long as the assets of the estate were sufficient to answer all claims, a State could not obtain an adjudication in this Court as to which State had "the jurisdiction and lawful right" to impose inheritance taxes. Only in the very rare situation when a decedent's estate was threatened with death tax claims of two or more States that together exceeded its assets, and only if one of the competing States then invoked this Court's original jurisdiction, would the Court undertake to decide the decedent's true domicile and grant one State the exclusive right to tax the decedent's estate. IV In reality the facts in Texas v. Florida, as well as the allegations in the complaint now before us, contain the seeds of two distinct lawsuits. One is a dispute between two States as to the proper division of a finite sum of money. The other is a suit in the nature of interpleader to settle the question of a decedent's domicile for purposes of the taxes to be imposed 601 STEWART, J., concurring upon his estate. But the suit in the nature of interpleader is not within the original and exclusive jurisdiction of this Court because it is not a dispute between States. And the dispute between the States, if indeed it is justiciable at all, is certainly not yet a case or controversy within the constitutional meaning of that term. A What California seeks in the present complaint is a determination of where Howard Hughes was domiciled at the time of his death. It is clear to me that, if presented by a proper party in a proper forum, this determination could and should be made in response to a bill of interpleader. See nn. 9 and 10, supra. But if interpleader generally affords no remedy to a decedent's estate that is faced with the threat of multiple taxation, there is no logical reason why the remedy should be available in the rare situation where the multiple taxation would wipe the estate out entirely. If it is unfair to subject an estate to two domicile-based taxes when all agree that it is possible to have only one domicile, that unfairness is just as great, if not greater, when a decedent's estate is able to pay the taxes to both States. It must be recognized, however, that what is involved is unfairness to the estate, not to the taxing States. The remedy of interpleader exists, if at all, to require litigation of the inconsistent tax claims in a single forum in order to avert the risk of loss to the estate that would result from separate adjudications. But the only live controversy in such a suit is between each State and the decedent's estate as to the legal obligation to pay death taxes. There is, in fact, no present dispute between the claiming States. In the present case, it would be of no possible concern to either California or Texas that the other might adjudge Hughes a domiciliary and succeed in taxing his estate, except for the possibility that the other's tax might exhaust the |