Understanding Preemption

Understanding the Doctrine of Preemption:

Under the Supremacy Clause of the U.S. Constitution, all federal law, including treaties, shall be the “supreme law of the land” and as such, supersede any state or local state in conflict with federal law. For example, the federal government may require that all U.S. citizens pay a federal tax. If the state of Washington mandated that its citizens do not pay the federal tax, the state of Washington’s law would be in violation of the Supremacy Clause. The federal tax law pre-empts Washington state’s tax law.

As the argument stands, some claim that Arizona’s new immigration law violates the Supremacy Clause or doctrine of preemption. State laws are pre-empted by federal law in two circumstances: 1) when there is a conflict with federal law or 2) when Congress has so thoroughly regulated a field that there is no room for even congruent state laws.

An example of (1): Los Angeles and San Francisco have become “sanctuary cities”. In both cities, the state of California has made it illegal for the police to contact ICE (a federal agency) to report illegal aliens. Hence, for illegal immigrants, they become a “sanctuary”. Because ICE is the mechanism by which federal immigration is enforced, the state of California’s law prohibiting its police force to contact ICE, is in violation of the Supremacy Clause.

An example of (2): If indeed, Arizona’s law agrees with federal law, Congress may have engaged in “field pre-emption” by occupying the entire field of immigration, thus prohibiting even harmonious state laws. Field pre-emption may arise, for example, in the case of federal health and safety laws, so that manufacturers of cars, medical devices, and drugs are not forced to comply with the laws of 50 different states to sell their products nationally. According to the Supreme Court’s most recent pre-emption ruling, Arizona’s law is not pre-empted because Congress did not expressly prohibit state regulation of illegal aliens.

De Canas v. Bica (1976), the Court held 8-0 that a California law prohibiting employers from hiring illegal immigrants was not pre-empted by federal law. Justice William Brennan concluded that “the federal government’s supremacy over immigration is strictly limited to: (1) a determination of who should or should not be admitted into the country and (2) the conditions under which a legal entrant may remain.” In short, there is no “field pre-emption” of state laws dealing with aliens, nor is there an explicit statement from Congress pre-empting state regulation of aliens.

Because the Arizona law precisely coincides with federal immigration law, and because the Court has ruled “field pre-emption” does not apply to immigration, the Arizona law is therefore constitutional. The Arizona law would be unconstitutional if and only if it is a violation of federal law to enforce or uphold federal immigration law.