A federal judged this week struck down a 2013 law that allowed Maine residents to purchase prescription drugs by mail from other countries. U.S. District Court Judge Nancy Torresen ruled on Monday that Maine’s law circumvented federal law, which permits state-to-state drug sales but prohibits international imports. Her decision renders the law invalid, but the state can appeal. A coalition of groups led by the Maine Pharmacy Association filed the lawsuit in September 2013, alleging that the new law was a threat to public safety.