[JURIST] The US Court of Appeals for the Ninth Circuit [official website] on Monday upheld [opinion, PDF] a lower court decision to enjoin several provisions of Arizona’s controversial immigration law [SB 1070 materials; JURIST news archive]. In July, the US District Court for the District of Arizona [official website] granted a preliminary injunction [JURIST report] to the Department of Justice (DOJ) [official website] blocking implementation of the law. Affirming the decision below, the Ninth Circuit held that “the district court did not abuse its discretion in finding that the United States demonstrated that it faced irreparable harm and that granting the preliminary injunction properly balanced the equities and was in the public interest.” In addressing the equities and public interest, the Ninth Circuit indicated that the constitutional infringement of the Supremacy Clause [text] alleged by the DOJ could itself constitute irreparable harm to the federal government absent injunctive relief:

We have found that “it is clear that it would not be equitable or in the public’s interest to allow the state … to violate the requirements of federal law, especially when there are no adequate remedies available. … In such circumstances, the interest of preserving the Supremacy Clause is paramount.”

The decision is expected to be appealed to the US Supreme Court [official website].

Last year, the DOJ sued [JURIST report] the state of Arizona and Governor Jan Brewer [official website] arguing that both the Constitution and federal law “do not permit the development of a patchwork of state and local immigration policies throughout the country.” The agency also claimed that the federal government has preeminent authority to regulate immigration matters and that the enforcement of the Arizona law is counterproductive to the national immigration policy. The Arizona law, which criminalizes illegal immigration and requires police officers to question an individual’s immigration status if the officer has a “reasonable suspicion” to believe an individual is in the country illegally, was signed into law [JURIST report] in April of last year. The law faces several additional legal challenges including a class-action law suit [JURIST report] filed by the American Civil Liberties Union (ACLU) [official website] on behalf of a number of advocacy groups and several private individuals. A challenge brought by several Tucson police officers claiming the law could not be properly implemented without racially profiling was dismissed [JURIST reports] late last year.