	Introduction

This report discusses state and local restrictions upon employing unauthorized aliens in light of the May 26, 2011, decision by the Supreme Court in Chamber of Commerce of the United States of America v. Whiting . 1070, which authorized or required the suspension or termination of the licenses of businesses that knowingly or intentionally hire unauthorized aliens, as well as required that employers in Arizona use the federal government's E-Verify database to check employees' work authorization. The doctrine of preemption derives from the Supremacy Clause of the Constitution, which establishes that federal law, treaties, and the Constitution itself are "the supreme Law of the Land." Thus, one essential aspect of the federal structure of government is that states can be precluded from taking actions that are otherwise within their authority if federal law is thereby thwarted. An act of Congress may preempt state or local action in a given area in any one of three ways: (1) the statute expressly states preemptive intent (express preemption); (2) a court concludes that Congress intended to occupy the regulatory field, thereby implicitly precluding state or local action in that area (field preemption); or (3) state or local action directly conflicts with or otherwise frustrates the purpose of the federal scheme (conflict preemption). In finding that LAWA was not preempted by federal immigration law, a majority of the Court apparently opens the door to additional state and local restrictions upon employing unauthorized aliens. Measures that would criminalize the seeking or performance of work by unauthorized aliens were not at issue in Whiting , but were found to be preempted in the Supreme Court's June 25, 2012, decision in Arizona v. United States . However, the INA did not originally regulate employment of unauthorized aliens. A number of states subsequently enacted measures prohibiting the employment of individuals who were not lawful residents of the United States. Federal regulation of the employment of unauthorized aliens expanded significantly in 1986, when the Immigration Reform and Control Act (IRCA) was enacted. Ten years later, Congress expanded upon IRCA's employment verification regime when it enacted the Illegal Immigration Reform and Immigrant Responsibility Act (IIRIRA). IIRIRA also provided that participation by private parties in the pilot programs is generally voluntary, and the Secretary of Homeland Security "may not require any person or other entity to participate." Some courts found that state licensing measures were within IRCA's "savings clause" even when the state independently determined whether an employer employed unauthorized aliens, and that IIRIRA did not prohibit a state from requiring use of E-Verify. Others found that such measures were preempted because the licensing provisions disrupted the balance struck by Congress between deterring illegal immigration, minimizing burdens on employers, and preventing discrimination against those perceived as "foreign," and Congress did not want use of E-Verify to be mandatory. Implications

The Supreme Court's decision in Whiting apparently opens the door to the enactment of additional state and local measures restricting the employment of unauthorized aliens. However, several lower court decisions subsequent to Whiting suggest that any state and local E-Verify measures, in particular, may need to parallel federal law to avoid being found to be preempted.
In May 2011, the Supreme Court ruled in Chamber of Commerce of the United States of America v. Whiting that federal immigration law did not preempt an Arizona statute that authorized or required the suspension or termination of the licenses of businesses that knowingly or intentionally hire unauthorized aliens, and also required that employers within Arizona use the federal government's E-Verify database to check employees' work authorization.
The doctrine of preemption derives from the Supremacy Clause of the U.S. Constitution, which establishes that federal law, treaties, and the Constitution itself are "the supreme Law of the Land." Thus, one essential aspect of the federal structure of government is that states can be precluded from taking actions that are otherwise within their authority if federal law is thereby thwarted. An act of Congress may preempt state or local action in a given area in any one of three ways: (1) the statute expressly states preemptive intent (express preemption); (2) a court concludes that Congress intended to occupy the regulatory field, thereby implicitly precluding state or local action in that area (field preemption); or (3) state or local action directly conflicts with or otherwise frustrates the purpose of the federal scheme (conflict preemption).
When it was enacted in 1952, the Immigration and Nationality Act (INA) did not regulate the employment of unauthorized aliens, and several states subsequently enacted measures prohibiting the employment of individuals who were not lawful residents of the United States. In a 1976 decision declining to find one such measure preempted, the Supreme Court recognized that it was "within the mainstream of [a state's] police power" to restrict the employment of aliens within their jurisdiction whose presence in the United States was not authorized by the federal government. However, in 1986, Congress enacted the Immigration Reform and Control Act (IRCA), which amended the INA to sanction employers of unauthorized aliens and expressly preempt states and localities from sanctioning employers other than through "licensing and similar laws." Then, in 1996, Congress enacted the Illegal Immigration Reform and Immigrant Responsibility Act (IIRIRA), which authorized the creation of a pilot program for verifying work authorization that ultimately developed into the program known as E-Verify. Under federal law, use of E-Verify by private entities is generally voluntary, and the Secretary of Homeland Security may not require persons or entities not specified in IIRIRA to participate.
Prior to Whiting, the federal courts of appeals had disagreed as to whether IRCA and IIRIRA preempted state and local measures like the Arizona statute. Some found that state licensing measures were within IRCA's "savings clause" even when the state independently determined whether an employer employed unauthorized aliens, and that IIRIRA did not prohibit states from requiring E-Verify use. Others found that licensing provisions disrupted the balance struck by Congress between deterring illegal immigration, minimizing burdens on employers, and preventing discrimination, and Congress did not want use of E-Verify to be mandatory.
The majority in Whiting relied primarily upon the "plain meaning" of IRCA and IIRIRA, while two dissents relied more heavily upon the legislative history and overall purpose of IRCA. The majority's decision apparently opens the door to additional state and local restrictions upon employing unauthorized aliens. However, several lower court decisions subsequent to Whiting suggest that any state and local E-Verify measures, in particular, may need to parallel federal law to avoid being found to be preempted. Measures that would criminalize the seeking or performance of work by unauthorized aliens were not at issue in Whiting, but were later found to be preempted in the Supreme Court's June 25, 2012, decision in Arizona v. United States.