Wisconsin Republicans’ 14-month investigation into the 2020 election results, which cost taxpayers $1.1 million and turned up no evidence of significant fraud, ended on Friday when the top G.O.P. lawmaker who first announced the inquiry fired the man he had entrusted to lead it.
Under pressure from former President Donald J. Trump and his allies, Robin Vos, the Republican speaker of the State Assembly, had moved in June 2021 to hire Michael J. Gableman, a conservative former Wisconsin Supreme Court justice, to scrutinize the state’s 2020 results.
But after weeks of open tension between Mr. Vos and Mr. Gableman — partly over the speaker’s refusal to entertain decertifying Joseph R. Biden Jr.’s victory in the state, and partly over Mr. Gableman’s endorsement of a primary challenger to Mr. Vos — the speaker said he was shutting down the investigation. The firing was first reported by The Associated Press.
Mr. Gableman has become a key driver of conspiracy theories about the 2020 election in Wisconsin and a ringleader of far-right Republicans’ effort to overturn the state’s presidential results, which cannot legally be done.
Mr. Vos told WISN-TV in Milwaukee that he had fired Mr. Gableman by letter and that the two had not spoken in recent weeks.
“I really don’t think there’s any need to have a discussion,” Mr. Vos said. “He did a good job last year, kind of got off the rails this year.”
Wisconsin Democrats, who have castigated Mr. Gableman and his investigation from its beginning, celebrated his firing and blasted Mr. Vos for hiring Mr. Gableman in the first place.
“Finally,” said Gov. Tony Evers, a Democrat.
Until now, Mr. Vos had remained publicly supportive of the state-funded investigation, even as Mr. Gableman amplified increasingly outlandish theories about the 2020 election. In March, the former justice presented state legislators with a report that said they should consider decertifying the election — a proposal that has no basis in state or federal law but that has nonetheless been adopted by Mr. Trump and his most ardent supporters in Wisconsin.
At an election-night party after his narrow victory on Tuesday, Mr. Vos said that Mr. Gableman was “an embarrassment to the state.”
In the following days, Mr. Vos defended his decision to start the Gableman investigation but signaled that he would soon end it.
“There were problems with the 2020 election that we need to fix — all of those things are real,” he said Wednesday on a conservative talk radio show in Milwaukee. “But somehow, Justice Gableman, as the investigation began to come to an end, decided it was more important to play to Donald Trump and to play to the very extreme of our party who thought we could unconstitutionally overturn the election than it was to be responsive to his client, which was the Legislature.”
Mr. Vos said in that interview that he had given Mr. Gableman “some very clear direction: ‘You can’t be involved in politics, you can’t go to rallies. We want you to be an independent voice.’ And he broke that.”
Yet when Mr. Vos announced the hire in June 2021, he did so at the Wisconsin Republican Party’s annual convention. And he did not publicly discipline Mr. Gableman when the former justice attended a political event with Mike Lindell, the MyPillow chief executive who has funded many attempts to overturn the election, or when he appeared at campaign events with local Republican Party chapters.
Mr. Vos and his spokeswoman did not respond to messages on Friday. Mr. Gableman’s spokesman, Zak Niemierowicz, said he had resigned from the investigation last month. Mr. Gableman did not respond to messages.
Francesca Hong, a state assemblywoman from Madison, was one of four Democratic legislators who demanded a state audit of Mr. Gableman’s work on Wednesday. On Friday, she said Mr. Vos was equally responsible.
“Michael Gableman, fully enabled & encouraged by Robin Vos, has been nothing but a conspiracy theorist and fraudster,” she wrote on Twitter, “sowing division in our state by undermining the integrity of our elections at a price tag of more than 1 million Wisconsin taxpayer dollars.”
Ben Wikler, the chairman of the Wisconsin Democratic Party, said in a statement, “Like Dr. Frankenstein, Robin Vos created a political monstrosity that wound up turning on its creator.”