particular exercise of governmental power from which the right may have arisen, if only the authority to enforce such right comes generally within the scope of the jurisdiction conferred by the government creating them"); Hart, The Relations Between State and Federal Law, 54 Colum. L. Rev. 489 (1954) (“The law which governs daily living in the United States is a single system of law"); see also Tafflin v. Levitt, 493 U. S. 455, 469 (1990) (SCALIA, J., concurring). 15 As Alexander Hamilton expressed the principle in a classic passage:

"[I]n every case in which they were not expressly excluded by the future acts of the national legislature, [state courts] will of course take cognizance of the causes to which those acts may give birth. This I infer from the nature of judiciary power, and from the general genius of the system. The judiciary power of every government looks beyond its own local or municipal laws, and in civil cases lays hold of all subjects of litigation between parties within its jurisdiction, though the causes of dispute are relative to the laws of the most distant part of the globe.

15 See also Worcester v. Georgia, 6 Pet. 515, 571 (1832) (McLean, J.): "It has been asserted that the federal government is foreign to the state governments; and that it must consequently be hostile to them. Such an opinion could not have resulted from a thorough investigation of the great principles which lie at the foundation of our system. The federal government is neither foreign to the state governments, nor is it hostile to them. It proceeds from the same people, and is as much under their control as the state governments.

"Where, by the Constitution, the power of legislation is exclusively vested in Congress, they legislate for the people of the Union, and their acts are as binding as are the constitutional enactments of a state legislature on the people of the state."

Congress, of course, may oust the state courts of their concurrent jurisdiction. See Yellow Freight System, Inc. v. Donnelly, 494 U. S. 820 (1990); Tafflin v. Levitt, 493 U. S. 455 (1990); Houston v. Moore, 5 Wheat. 1, 25-26 (1820).

Those of Japan, not less than of New York, may furnish the objects of legal discussion to our courts. When in addition to this we consider the State governments and the national governments, as they truly are, in the light of kindred systems, and as parts of ONE WHOLE, the inference seems to be conclusive, that the State courts would have a concurrent jurisdiction in all cases arising under the laws of the Union, where it was not expressly prohibited." The Federalist No. 82, p. 132 (E. Bourne ed. 1947) (emphasis added).

Three corollaries follow from the proposition that “federal” law is part of the "Law of the Land" in the State:

1. A state court may not deny a federal right, when the parties and controversy are properly before it, in the absence of "valid excuse." Douglas v. New York, N. H. & H. R. Co., 279 U. S. 377, 387-388 (1929) (Holmes, J.).16 "The ex

16 See Hathorn v. Lovorn, 457 U. S. 255, 263 (1982); Barr v. City of Columbia, 378 U. S. 146, 149 (1964); NAACP v. Alabama ex rel Patterson, 357 U. S., at 455; Rogers v. Alabama, 192 U. S. 226, 230-231 (1904); Eustis v. Bolles, 150 U. S. 361 (1893); Hill, The Inadequate State Ground, 65 Colum. L. Rev. 943, 954-957 (1965).

To understand why this is so, one need only imagine a contrary system in which the Supremacy Clause operated as a constraint on the activity of state-court judges like that imposed on other state actors, rather than as a rule of decision. On that hypothesis, state courts would be subject to the ultimate superintendence of federal courts which would vacate judgments entered in violation of federal law, just as they might overturn unconstitutional state legislative or executive decisions. Federal courts would exercise a superior authority to enforce and apply the Constitution and laws passed pursuant to it. See Wechsler, The Appellate Jurisdiction of the Supreme Court: Reflections on the Law and the Logistics of Direct Review, 34 Wash. & Lee L. Rev. 1043, 1047 (1977) (describing, and rejecting, alternative view of Supremacy Clause, as intrusion on state autonomy). The language of the Supremacy Clause-which directs that "the Judges in every State shall be bound thereby, any Thing in the Constitution or Laws of any state to the Contrary notwithstanding"-and our cases confirm that state courts have the coordinate authority and consequent

istence of the jurisdiction creates an implication of duty to exercise it." Mondou v. New York, N. H. & H. R. Co., 223 U. S. 1, 58 (1912); see Testa v. Katt, 330 U. S. 386 (1947); Missouri ex rel. St. Louis, B. & M. R. Co. v. Taylor, 266 U. S. 200, 208 (1924); Robb v. Connolly, 111 U. S. 624, 637 (1884).17

responsibility to enforce the supreme law of the land. Early in our history, in support of the Court's power of review over state courts, Justice Story anticipated that such courts "in the exercise of their ordinary jurisdiction . . . would incidentally take cognizance of cases arising under the constitution, the laws, and treaties of the United States," Martin v. Hunter's Lessee, 1 Wheat., at 342, and would decide federal questions even when, pleaded in replication, they were necessary to the plaintiff's case. Id., at 340. The adequate-state-ground doctrine accords respect to state courts as decisionmakers by honoring their modes of procedure. The structure of our system of judicial review, the requirement that a federal question arising from a state case must first be presented to the state courts for decision, see, e. g., Cardinale v. Louisiana, 394 U. S. 437 (1969); State Farm Mutual Automobile Ins. Co. v. Duel, 324 U. S. 154, 160–161 (1945); McGoldrick v. Compagnie Generale Transatlantique, 309 U. S. 430, 434 (1940), and the rule that a federal district court cannot entertain an original action alleging that a state court violated the Constitution by giving effect to an unconstitutional state statute, see Rooker v. Fidelity Trust Co., 263 U. S. 413, 415-416 (1923) ("If the constitutional questions stated in the bill actually arose in the cause, it was the province and duty of the state courts to decide them; and their decision, whether right or wrong, was an exercise of jurisdiction. . . . Unless and until so reversed or modified, it would be an effective and conclusive adjudication"); see also District of Columbia Court of Appeals v. Feldman, 460 U. S. 462, 476, 483-484, n. 16 (1983), all also presuppose that state courts presumptively have the obligation to apply federal law to a dispute before them and may not deny a federal right in the absence of a valid excuse.

17 Amici argue that the obligation of state courts to enforce federal law rests, not on the Supremacy Clause, but on a presumption about congressional intent and that Congress should be explicit when it intends to make federal claims enforceable in state court. Brief for Washington Legal Foundation et al. as Amici Curiae 8-9, 13. The argument is strikingly similar to the argument that we addressed in Minneapolis & St. Louis R. Co. v. Bombolis, 241 U. S. 211 (1916), when we held that state courts need not comply with the Seventh Amendment in hearing a federal statutory claim. We rejected the argument that "state courts [had] become courts

2. An excuse that is inconsistent with or violates federal law is not a valid excuse: The Supremacy Clause forbids state courts to dissociate themselves from federal law because of disagreement with its content or a refusal to recognize the superior authority of its source. "The suggestion that the act of Congress is not in harmony with the policy of the State, and therefore that the courts of the State are free to decline jurisdiction, is quite inadmissible because it presupposes what in legal contemplation does not exist. When Congress, in the exertion of the power confided to it by the Constitution, adopted that act, it spoke for all the people and all the States, and thereby established a policy for all. That policy is as much the policy of [the State] as if the act had emanated from its own legislature, and should be respected accordingly in the courts of the State." Mondou, 223 U. S., at 57; see Miles v. Illinois Central R. Co., 315 U. S. 698, 703-704

of the United States exercising a jurisdiction conferred by Congress, whenever the duty was cast upon them to enforce a Federal right." Id., at 222. We reject it again today. We stated in Bombolis:

"It is true in the Mondou Case it was held that where the general jurisdiction conferred by the state law upon a state court embraced otherwise causes of action created by an act of Congress, it would be a violation of duty under the Constitution for the court to refuse to enforce the right arising from the law of the United States because of conceptions of impolicy or want of wisdom on the part of Congress in having called into play its lawful powers. But that ruling in no sense implied that the duty which was declared to exist on the part of the state court depended upon the conception that for the purpose of enforcing the right the state court was to be treated as a Federal court deriving its authority not from the State creating it, but from the United States. On the contrary the principle upon which the Mondou Case rested, while not questioning the diverse governmental sources from which state and national courts drew their authority, recognized the unity of the governments, national and state, and the common fealty of all courts, both state and national, to both state and national constitutions, and the duty resting upon them, when it was within the scope of their authority, to protect and enforce rights lawfully created, without reference to the particular government from whose exercise of lawful power the right arose." Id., at 222–223.

See also Tafflin v. Levitt, 493 U. S., at 469-470 (SCALIA, J., concurring).

(1942) (“By virtue of the Constitution, the courts of the several states must remain open to such litigants on the same basis that they are open to litigants with causes of action springing from a different source"); McKnett v. St. Louis & San Francisco R. Co., 292 U. S. 230, 233-234 (1934); Minneapolis & St. Louis R. Co. v. Bombolis, 241 U. S. 211 (1916); cf. FERC v. Mississippi, 456 U. S. 742, 776, n. 1 (1982) (opinion of O'CONNOR, J.) (State may not discriminate against federal causes of action).

3. When a state court refuses jurisdiction because of a neutral state rule regarding the administration of the courts, we must act with utmost caution before deciding that it is obligated to entertain the claim. See Missouri ex rel. Southern R. Co. v. Mayfield, 340 U. S. 1 (1950); Georgia Rail Road & Banking Co. v. Musgrove, 335 U. S. 900 (1949) (per curiam); Herb v. Pitcairn, 324 U. S. 117 (1945); Douglas v. New York, N. H. & H. R. Co., 279 U. S. 377 (1929). The requirement that a state court of competent jurisdiction treat federal law as the law of the land does not necessarily include within it a requirement that the State create a court competent to hear the case in which the federal claim is presented. The general rule, "bottomed deeply in belief in the importance of state control of state judicial procedure, is that federal law takes the state courts as it finds them." Hart, 54 Colum. L. Rev., at 508; see also Southland Corp. v. Keating, 465 U. S. 1, 33 (1984) (O'CONNOR, J., dissenting); FERC v. Mississippi, 456 U. S., at 774 (opinion of Powell, J.). The States thus have great latitude to establish the structure and jurisdiction of their own courts. See Herb, supra; Bombolis, supra; Missouri v. Lewis, 101 U. S. 22, 30-31 (1880). In addition, States may apply their own neutral procedural rules to federal claims, unless those rules are pre-empted by federal law. See Felder v. Casey, 487 U. S. 131 (1988); James v. Kentucky, 466 U. S., at 348.

These principles are fundamental to a system of federalism in which the state courts share responsibility for the applica