Billionaire Elon Musk has given away $1m (£770,000) cheques to voters in Wisconsin after the state supreme court refused to intervene.

Musk announced the prize earlier this week, ahead of Wisconsin’s tightly contested Supreme Court election to be held on Tuesday.

Wisconsin Attorney General and Democrat Josh Kaul had sued to stop the giveaway, arguing that Musk was violating a state law that bans gifts in exchange for votes.

The race, which could flip control of the state’s supreme court to the Republicans, has become a flash point and the most expensive judicial election in American history.

Speaking at a rally Sunday night, Musk said “we just want judges to be judges”, before handing out two $1m (£750,000) cheques to voters who had signed a petition to stop “activist” judges.

Kaul had tried to argue the giveaway was an illegal attempt buy votes. Musk’s lawyers, in response, argued that Kaul is “restraining Mr Musk’s political speech and curtailing his First Amendment rights”.

Musk’s lawyers added that the payments were “intended to generate a grassroots movement in opposition to activist judges, not to expressly advocate for or against any candidate”.

After two lower courts sided with Musk, Kaul begged the state’s supreme court for an 11th hour reprieve. But the top court unanimously declined to hear the case.

Musk and President Donald Trump have endorsed a conservative candidate, Waukesha County Judge Brad Schimel, in hopes of flipping the liberal-leaning court.

Judge Schimel is running against Dane County Judge Susan Crawford, who has been endorsed by the state Supreme Court’s liberal justices.

Lawyers for the tech titan also argued that judges who have publicly endorsed Judge Crawford in the Supreme Court race should be barred from ruling on the matter, arguing that it is a matter of bias.

Wisconsin’s Supreme Court race is being seen by political watchers as a referendum on Trump’s second term, just months after his inauguration.

It also comes ahead of consequential cases that will land before the court on abortion rights, congressional redistricting and voting rules that could affect the 2026 midterm elections.

Musk himself has framed the election as a chance to stop redistricting which could give Democrats favour in Congress.

He has donated $14m to Judge Schimel’s campaign, as the race proves to be the most expensive judicial race in the country’s history, with $81m in total spending.

Despite his support, Judge Schimel appeared to distance himself from Musk in recent days, telling the Milwaukee Journal Sentinel on Friday he had no plans to be at the rally.

“I have no idea what he’s doing. I have no idea what this rally is,” Judge Schimel told the newspaper.

This is not the first time Musk has announced a giveaway to voters. Last year, he similarly offered a cash prize of $1m a day to voters in Wisconsin and six other battleground states if they signed a petition supporting First and Second Amendment rights.

A judge in Pennsylvania later ruled that the giveaway was legal, saying prosecutors failed to prove it was an unlawful lottery.