Today, it is widely accepted that the Constitution authorizes courts to review and invalidate state laws that conflict with federal statutes. At the same time, prominent commentators and even some judges maintain that courts should not seriously review the constitutionality of federal statutes alleged to exceed the scope of Congress' enumerated powers. In their view, the constitutional structure protects the states (and thereby reduces the need for judicial review of federal power), but establishes no comparable safeguards to deter states from interfering with federal prerogatives. Contrary to this position, there is an express textual basis for judicial review of federal statutes alleged to exceed Congress' enumerated powers. The Supremacy Clause establishes a rule of decision for courts adjudicating the rights and duties of parties under both state and federal law. Under our federal system, the States possess sovereignty concurrent with that of the Federal Government, subject only to limitations imposed by the Supremacy Clause. The Clause, in turn, designates as the supreme Law of the Land only those Laws of the United States . . . made in Pursuance of the Constitution. If a federal statute satisfies this condition, courts must apply the statute notwithstanding contrary state law. If the federal statute fails this condition, however, it does not qualify as the supreme Law of the Land and courts remain free to apply state law. Thus, in order to apply the Supremacy Clause, courts must necessarily consider and resolve challenges to the constitutionality of federal statutes. The text, history, and structure of the Constitution confirm that the Supremacy Clause authorizes judicial review of federal statutes alleged to exceed the scope of federal power. The Founders considered three alternative mechanisms for resolving conflicts between state and federal law: coercive military force, congressional power to negative state laws, and adjudication under the Supremacy Clause. The decision to enlist courts - rather than Congress or the President - indicates that the Founders preferred to treat conflicts between state and federal law as judicial, rather than political questions. In addition, by expressly conditioning the supremacy of federal statutes on their constitutionality, the Supremacy Clause reassured the states that courts (both federal and state) would keep the federal government within the bounds of its assigned powers. Thus, in effect, the Clause reserves all remaining powers to the states, or to the people. These conclusions find support in the Supreme Court's early invocation of the Supremacy Clause to explain judicial review of federal statutes in cases like McCulloch v. Maryland and Gibbons v. Ogden.
Bradford R. Clark, The Supremacy Clause as a Constraint on Federal Power, 71 Geo. Wash. L. Rev. 91 (2003).