In
Marbury v. Madison, 5 U.S. 137 (1803), the Supreme Court held that Congress cannot pass laws that are contrary to the Constitution, and it is the role of the judicial system to interpret what the Constitution permits. Citing the Supremacy Clause, the Court found Section 13 of the
Judiciary Act of 1789 to be unconstitutional to the extent it purported to enlarge the original jurisdiction of the Supreme Court beyond that permitted by the Constitution. In ''
Martin v. Hunter's Lessee, 14 U.S. 304 (1816), and Cohens v. Virginia'', 19 U.S. 264 (1821), the Supreme Court held that the Supremacy Clause and the judicial power granted in Article III give the Supreme Court the ultimate power to review state court decisions involving issues arising under the Constitution and laws of the United States. Therefore, the Supreme Court has the final say in matters involving federal law, including constitutional interpretation, and can overrule decisions by state courts. In
McCulloch v. Maryland, 17 U.S. (4 Wheat.) 316 (1819), the Supreme Court reviewed a tax levied by
Maryland on the federally incorporated Bank of the United States. The Court found that if a state had the power to tax a federally incorporated institution, then the state effectively had the power to destroy the federal institution, thereby thwarting the intent and purpose of Congress. This would make the states superior to the federal government. The Court found that this would be inconsistent with the Supremacy Clause, which makes federal law superior to state law. The Court therefore held that Maryland's tax on the bank was unconstitutional because the tax violated the Supremacy Clause. In
Ableman v. Booth, 62 U.S. 506 (1859), the Supreme Court held that state courts cannot issue rulings that contradict the decisions of federal courts, citing the Supremacy Clause, and overturning a decision by the Supreme Court of
Wisconsin. Specifically, the court found it was illegal for state officials to interfere with the work of U.S. Marshals enforcing the
Fugitive Slave Act or to order the release of federal prisoners held for violation of that Act. The Supreme Court reasoned that because the Supremacy Clause established federal law as the law of the land, the Wisconsin courts could not nullify the judgments of a federal court. The Supreme Court held that under Article III of the Constitution, the federal courts have the final jurisdiction in all cases involving the Constitution and laws of the United States, and that the states therefore cannot interfere with federal court judgments. In
Pennsylvania v. Nelson, 350 U.S. 497 (1956) the Supreme Court struck down the
Pennsylvania Sedition Act, which made advocating the forceful overthrow of the federal government a crime under Pennsylvania state law. The Supreme Court held that when federal interest in an area of law is sufficiently dominant, federal law must be assumed to preclude enforcement of state laws on the same subject; and a state law is not to be declared a help when state law goes farther than Congress has seen fit to go. In
Cooper v. Aaron, 358 U.S. 1 (1958), the Supreme Court rejected attempts by
Arkansas to nullify the Court's school desegregation decision,
Brown v. Board of Education. The state of Arkansas, acting on a theory of
states' rights, had adopted several statutes designed to nullify the desegregation ruling. The Supreme Court relied on the Supremacy Clause to hold that the federal law controlled and could not be nullified by state statutes or officials. In
Edgar v. MITE Corp., , the Supreme Court ruled: "A state statute is void to the extent that it actually conflicts with a valid Federal statute". In effect, this means that a state law will be found to violate the Supremacy Clause when either of the following two conditions (or both) exist: • Compliance with both the Federal and State laws is impossible • "State law stands as an obstacle to the accomplishment and execution of the full purposes and objectives of Congress" The Supreme Court has also held that only specific, "unmistakable" acts of Congress may be held to trigger the Supremacy Clause.
Montana had imposed a 30 percent tax on most
sub-bituminous coal mined there. The
Commonwealth Edison Company and other
utility companies argued, in part, that the Montana tax "frustrated" the broad goals of the federal energy policy. However, in the case of
Commonwealth Edison Co. v. Montana, , the Supreme Court disagreed. Any appeal to claims about "national policy", the Court said, were insufficient to overturn a state law under the Supremacy Clause unless "the nature of the regulated subject matter permits no other conclusion, or that the Congress has unmistakably so ordained". However, in the case of
California v. ARC America Corp., , the Supreme Court held that if Congress expressly
intended to act in an area, this would trigger the enforcement of the Supremacy Clause, and hence nullify the state action. The Supreme Court further found in
Crosby v. National Foreign Trade Council, , that even when a state law is not in direct conflict with a federal law, the state law could still be found unconstitutional under the Supremacy Clause if the "state law is an obstacle to the accomplishment and execution of Congress's full purposes and objectives". Congress need not expressly assert any preemption over state laws either, because Congress may implicitly assume this preemption under the Constitution. Finally, in
Murphy v. National Collegiate Athletic Association, the Supreme Court enforced the Supremacy Clause by overturning Federal law as an unconstitutional encroachment into the domain of the states not within of the limits of the
Delegated powers, stating that the "Constitution confers on Congress not plenary legislative power but only certain enumerated powers". ==See also==