United States President Donald Trump's popularity is on the line for Tuesday's election in Wisconsin, for which his high-profile aide, Elon Musk, distributed million-dollar cheques to voters.
Since returning to the White House in January, Trump has introduced sweeping reforms, dismantling significant portions of the federal government, altering foreign policy, and instigating trade wars that threaten to reignite inflation.
While his focus on migrants, judges, "woke" culture, and critics has garnered praise from supporters, these approaches remain largely untested among the broader electorate.
The Wisconsin election features conservative candidate Brad Schimel facing off against liberal Susan Crawford for a supreme court seat. A Schimel victory would shift the court's balance to the right, while Crawford win would maintain its liberal majority.
Musk has argued that a conservative win is needed to cement Trump's national agenda, with the supreme court race having an impact on a potential redrawing of Congressional districts in the swing state ahead of midterm elections next year.
Trump's Republican party in Washington holds a slim 218-213 majority in the House of Representatives over Democrats and an even slimmer lead in the Senate.
Trump attacked Crawford on social media on Monday, accusing her of "letting child molesters and rapists off easy".
"She will be one of the most Liberal Judges ever elected, which would be a DISASTER for Wisconsin and, the United States of America," he said.
Also on Tuesday, voters in Florida will elect members of the House in two heavily Republican districts, which were vacated by Trump's National Security Advisor Mike Waltz and his original nominee for attorney general, Matt Gaetz.
The Wisconsin poll is expected to be close, with Trump narrowly beating his Democratic rival Kamala Harris in last year's presidential election by less than 30,000 votes in the state.
Musk, who spent roughly $277 million on Trump's election campaign, has piled more resources into the Wisconsin vote.
He has handed out two prize cheques of $1 million each to voters, and also given $100 each to voters who sign his petition against "activist judges".
According to the Brennan Center for Justice, more than $49.7 million has been spent by Schimel and his backers, including $12.2 million from Musk's America PAC.
Crawford's campaign and those backing her have spent an estimated $40.3 million.
The spending has made the Wisconsin race the most expensive in US judicial history, the institute said.
Crawford has accused Tesla owner Musk of seeking to buy a seat on the state supreme court to swing judgments in favour of his companies.
A case regarding car dealerships filed by the electric vehicle manufacturer is potentially headed to the court.
Speaking at a campaign rally on Sunday, Musk placed the national political context front and centre.
"What's happening on Tuesday is a vote for which party controls the US House of Representatives," Musk declared, arguing that Congress was so evenly balanced that Wisconsin's seats could decide its majority in the 2026 midterms.
The billionaire's Green Bay rally had an enthusiastic crowd, but the South African-born oligarch's role in Wisconsin elections has provoked as much resistance as support.
At a pro-Crawford rally, 65-year-old retired electrical engineer Rob Patterson held up a sign showing Musk giving a straight-armed salute.
"Our Supreme Court is not for sale," the sign read.