Voting in Wisconsin will proceed as scheduled on Tuesday, after conservative majorities on the federal and state supreme courts blocked Democratic efforts to extend balloting for days or weeks to reduce public gatherings during the coronavirus pandemic.

Late Monday, the U.S. Supreme Court by a 5-4 vote overturned lower-court orders extending by six days the deadline for mailing absentee ballots. The high court’s action came shortly after the Wisconsin Supreme Court invalidated an executive order by Gov. Tony Evers rescheduling the election to June 9. Both cases saw all conservative justices side with Republicans who were seeking to maintain voting on Tuesday, while all liberal justices agreed with Democratic arguments to extend balloting in response to the contagion.

The rulings mean Wisconsin is set to buck the trend in other states; more than a dozen have postponed elections to comply with public-health recommendations to limit contact between people during the pandemic. Polls have shown former Vice President Joe Biden leading in the state’s Democratic presidential primary. President Trump is unopposed in the GOP’s. Local and state races are on the ballot as well.

State Republican leaders applauded the rulings and pointed out that voters have requested over a million absentee ballots. “This prudent action by the United States Supreme Court addresses our concerns over ballot security in tomorrow’s election,” Wisconsin Senate Majority Leader Scott Fitzgerald and Assembly Speaker Robin Vos said. “We look forward to the voting tomorrow being secure.”

Mr. Evers said that allowing the election to proceed goes against the advice of public-health experts. “Tomorrow in Wisconsin, thousands will wake up and have to choose between exercising their right to vote and staying healthy and safe,” he said.