The US Federal Government’s challenging of Arizona’s container border wall has been widely reported in the media. The US Federal Government has challenged the placement of these containers as “damaging federal lands, threatening public safety, and impeding the ability of federal agencies and officials, including law enforcement personnel, to perform their official duties.”
While Arizona has agreed to remove the containers, Arizona state government action raises important questions regarding federal pre-emption of state law.
The Supremacy Clause gives Congress the power to preempt state law. A statute may contain an express preemption provision, see, e.g., Chamber of Commerce of United States of America v. Whiting, 563 U. S. 582, but state law must also give way to federal law in at least two other circumstances. First, States are precluded from regulating conduct in a field that Congress has determined must be regulated by its exclusive governance. See Gade v. National Solid Wastes Management Assn., 505 U. S. 88, 115. Intent can be inferred from a framework of regulation “so pervasive . . . that Congress left no room for the States to supplement it” or where a “federal interest is so dominant that the federal system will be assumed to preclude enforcement of state laws on the same subject.” Rice v. Santa Fe Elevator Corp., 331 U. S. 218, 230. Second, state laws are preempted when they conflict with federal law, including when they stand “as an obstacle to the accomplishment and execution of the full purposes and objectives of Congress.” Hines v. Davidowitz, 312 U. S. 52, 67. Pp. 7–8.
The Supremacy Clause of the United States Constitution, found in Article VI, states that the federal Constitution, and federal law generally, take precedence over state laws, even over state constitutions. This means that when there is a conflict between state and federal law, the federal law will generally be supreme and will be the law that is followed.
One example of a recent conflict between state and federal law is United States v. Washington, 596 U. S. ____ (2022). In 2018, Washington enacted a workers’ compensation law that applied only to certain workers at a federal facility in the State who were “engaged in the performance of work, either directly or indirectly, for the United States.” Wash. Rev. Code §51.32.187(1)(b). The federal facility called the Hanford site, had previously been used by the US Government for the development and production of nuclear weapons. Hanford is no longer being used for this purpose, and so is currently undergoing complex decontamination. Most workers cleaning this site are federal contractors for the Federal Government, though a smaller number are Washington State, private, and federal employees. As it compares to the Washington general workers’ compensation law, this particular Hanford-focused state law makes it easier for federal contractors to establish their entitlement to workers’ compensation, which in turn increases worker compensation costs for the Federal Government.
The United States sued Washington under the argument that the Washington State law violates the Supremacy Clause by discriminating against the Federal Government. Lower courts held that the law was constitutional because it fell within the scope of a federal waiver of immunity contained in 40 U. S. C. §3172. However, the Supreme Court Determined that Washington’s law facially discriminates against the Federal Government and its contractors. Because §3172 does not clearly and unambiguously waive the Federal Government’s immunity from discriminatory state laws, Washington’s law has been ruled unconstitutional under the Supremacy Clause.
Another example of a conflict between state and federal law occurred in the case of Gonzales v. Raich, in which the state of California and two individuals challenged the federal Controlled Substances Act, which criminalized the possession and distribution of certain drugs, including marijuana. California had passed a state law allowing for the use of marijuana for medicinal purposes, and the individuals argued that the federal law was unconstitutional as applied to their possession and use of marijuana for medicinal purposes. However, the Supreme Court held that the federal law was a valid exercise of Congress's power to regulate interstate commerce, and therefore preempted any conflicting state laws.
In both of these cases, the Supremacy Clause played a key role in determining the outcome. The Supremacy Clause generally ensures that federal law is supreme over state law, and that federal law takes precedence in cases of conflict. This established precedent helps ensure that there is a uniform system of law throughout the United States, and that the federal government has the power to enforce its laws throughout the country. It is an important part of the US Constitution and US law, and provides the federal government with the necessary power to carry out its duties and responsibilities.