[JURIST] The US District Court for the Western District of Oklahoma [official website] granted a preliminary injunction [order, PDF] Wednesday blocking the enforcement of employer-related provisions of Oklahoma's controversial immigration law [HB 1804 text, DOC]. Judge Robin Cauthron concluded that it is "substantially likely" that the provisions are preempted by federal immigration law, and that there was a risk of harm to the plaintiffs if the challenged provisions were to come into effect on July 1, 2008. The US Chamber of Commerce [official website], one of the named plaintiffs, applauded [Chamber of Commerce press release] the court's decision to delay enforcement, maintaining that "through harsh civil penalties, the Oklahoma law unfairly shifts the burden of immigration enforcement from government onto the backs of businesses." Additional proceedings are required in Chamber of Commerce of the United States, et. al. v. Henry before the court decides whether to grant the requests for declaratory relief and a permanent injunction [PDF, complaint]. AP has more.

HB 1804, which has been called the toughest illegal immigration statute in the nation, requires employers doing business with the state to verify the eligibility of their employers with the federal government's E-Verify program [DHS backgrounder]. The law imposes strong civil sanctions against employers who fail to comply with the law, including increased tax rates, the loss of contracts, and exposure to litigation if an employer “should have known” that an employee was unauthorized to work. In January, the law was challenged [JURIST report] in Oklahoma state court. In October 2007, the US District Court for the Northern District of Oklahoma [official website] dismissed an earlier lawsuit [JURIST report] challenging the law because the plaintiffs had suffered no cognizable injury as a result of its enforcement.