The victory, by upward of 120,000 votes as of Monday night, came as a shock to Republicans and Democrats alike in Wisconsin, where contests for president, governor and the state’s high court in the last four years have all been decided by about 30,000 votes or less. It followed weeks of Democratic anger over Republicans’ insistence on holding elections amid the coronavirus pandemic.

Wisconsin’s map on Monday night looked like a dream general election result for former Vice President Joseph R. Biden Jr., the presumptive Democratic nominee — stronger than typical for Democrats in the suburbs and a respectable showing among the state’s blue-collar white voters in rural counties. But officials from both parties cautioned against overinterpreting the Supreme Court results, given the bizarre circumstances surrounding the high court race.

The challenger for the court seat, Jill Karofsky, ousted the conservative incumbent, Justice Daniel Kelly, in a contest with broad potential implications for voting rights in Wisconsin’s November general election. Justice Kelly became just the second incumbent State Supreme Court justice to be ousted at the polls since 1967. President Trump had boasted that his endorsement of Justice Kelly had unnerved Democrats in the state.