ST. PAUL, Minn. — A Democratic legislator from Minnesota apologized yesterday for a tweet he sent that referred to Supreme Court Justice Clarence Thomas as “Uncle Thomas” following a ruling on the nation’s voting-rights law.

Thomas, who is black, was part of a 5-4 majority that invalidated part of the Voting Rights Act. The ruling makes it tougher to prevent states and localities from adopting policies that make voting difficult. In response, state Rep. Ryan Winkler tweeted, “majority is four accomplices to race discrimination and one Uncle Thomas.”