DETROIT – A federal judge has ruled that a Michigan law that bars retailers from selling or renting violent video games to minors is unconstitutional.

The Entertainment Software Association, Video Software Dealers Association, and Michigan Retailers Association, trade groups representing American computer and video game publishers, filed a lawsuit in September, charging that the law is unconstitutionally vague and limits First Amendment rights.

Governor Jennifer Granholm signed the law in September, and it was scheduled to take effect December 1. But U.S. District Judge George Steeh issued a preliminary injunction in November, putting the law on hold. Judge Steeh’s ruling on Friday made the injunction permanent.

“Video games contain creative, expressive free speech, inseparable from their interactive functional elements, and are therefore protected by the First Amendment,” he said in his ruling.

Douglas Lowenstein, president of the Entertainment Software Association, applauded the decision in a statement, saying it “represents a sweeping rejection of the state’s claims regarding the harmful effects of violent video games.”

“We … will be reviewing the judge’s order and discussing legal options, including an appeal at the attorney general’s office,” said Heidi Watson, a spokeswoman for Ms. Granholm. “But we will continue our efforts to protect kids from violent video games by working with retailers.”