The Supreme Court is letting stand a lower court's ruling barring Florida from enforcing a contentious immigration law that imposes criminal penalties against undocumented migrants who enter the state.

The law, enacted this year, made it a crime for unauthorized migrants to enter the state. Challengers say immigration is a federal matter.

Florida passed a law making it a crime for people in the U.S. illegally to enter the state. A federal judge said it's likely unconstitutional.