The immigration law has faced numerous challenges in court since it took effect in September. Last month, the US Department of Justice (DOJ) [official website] filed a brief [JURIST report] in the US Court of Appeals for the Eleventh Circuit urging the court to strike down the law. The DOJ filed its brief in response to a federal judge's September 28 ruling [opinion text] that allowed the state to enforce a provision that makes it a felony for an illegal alien to conduct business with the state, among other provisions. The DOJ argued in its brief that the Alabama immigration laws are preempted by federal laws regulating immigration in the US because of the Supremacy Clause [Cornell LII backgrounder] in the US Constitution. The American Civil Liberties Union (ACLU) [advocacy website] filed a separate brief also asking the court to overturn the new law. The ACLU's brief argued that the laws are designed to make life in Alabama so difficult for illegal aliens that they will be forced to leave the state [JURIST op-ed]. Like the DOJ, the ACLU argued that Alabama's law is a direct attempt to regulate immigration, which is an area that the states have no legitimate interest in regulating and is left only to the federal government to legislate.