First, Wisconsin Republicans ordered an audit of the 2020 election. Then they passed a raft of new restrictions on voting. And in June, they authorized the nation’s only special counsel investigation into 2020.

Now, more than 15 months after the 2020 election, a segment of the Republican Party is getting behind a new plan: decertifying the results of the 2020 presidential election in hopes of reinstalling Mr. Trump in the White House.

Wisconsin is closer to the next federal election than the last, but the Republican effort to overturn the election results here is picking up steam rather than fading away — and spiraling further from reality as it goes. The latest turn is creating chaos in the Republican Party and threatening to undermine its push to win the contests this year for governor and the Senate.

In Wisconsin, Robin Vos, the Assembly speaker, is now struggling to rein them in.

“This is a real issue,” said Timothy Ramthun, the Republican state representative who has turned his push to decertify the election into a nascent campaign for governor. Mr. Ramthun has asserted that if the Wisconsin Legislature decertifies the results and rescinds the state’s 10 electoral votes — an action with no basis in state or federal law — it could set off a movement that would oust President Biden from office.

“We don’t wear tinfoil hats,” he said. “We’re not fringe.”

Nearly two-thirds of Wisconsin Republicans were not confident in the state’s 2020 presidential election results, according to an October poll from the Marquette University Law School in Milwaukee.

“This is just not what the Republican Party needs right now,” said Rob Swearingen, a Republican state representative from the conservative Northwoods. “We shouldn’t be fighting among ourselves about what happened, you know, a year and a half ago.”

Wisconsin has the nation’s most active decertification effort. In Arizona, a Republican state legislator running for secretary of state, along with candidates for Congress, has called for recalling the state’s electoral votes. In September, Mr. Trump wrote a letter to Georgia officials asking them to decertify Mr. Biden’s victory there, but no organized effort materialized.

What would you like to see in Wisconsin?