A federal judge in Miami has blocked the enforcement of a new Florida law that criminalizes the actions of undocumented workers who enter or re-enter the state, finding that plaintiffs who filed the lawsuit may prevail in their argument that the law is unconstitutional.

Judge Kathleen Williams of the Southern District of Florida made the decision on April 4 to put in place a temporary restraining order to prevent enforcement of Senate Bill 4-C, which took effect in February. The measure prohibits any “unauthorized alien” age 18 or older from entering the state after illegally crossing into U.S. territory. A first conviction is a first-degree misdemeanor with a minimum punishment of nine months in prison, while subsequent convictions are felonies with escalating minimum sentences.

The plaintiffs in the lawsuit include undocumented individuals living in Florida as well as the Farmworker Association of Florida and the Florida Immigrant Coalition. They argue that the new state law is a legislative overreach into an area exclusively reserved for the federal government, that it conflicts with existing federal immigration law and that it violates the Constitution’s Supremacy Clause.