Nomia Iqbal and Cai Pigliucci
BBC News
Reporting fromMilwaukee, Wisconsin
Getty Images
It's only been five months since voters in Wisconsin faced a bitterly fought election, but residents of the US state are already heading back to the polls.
This time, Elon Musk looms large in the race to fill a vacancy on the Wisconsin Supreme Court, even if the billionaire's name doesn't appear on the ballot.
It's the most expensive judicial contest in US history, with more than $90m (£70m) spent so far, including $20m from Musk and groups affiliated with him.
The choice is between conservative Brad Schimel, backed by President Donald Trump and Musk, and liberal Susan Crawford, who is supported by former President Barack Obama and Democratic mega-donors like George Soros.
It's forecast to be a tight contest that could flip control of the Midwestern state's top court, which is currently controlled 4-3 by liberal justices.
But it's also one of the first real tests of voter sentiment towards Trump, in a state that he won by less than a percentage point during his decisive White House election victory last November.
"I hate Musk!" said Wisconsin voter Peggy
The Republican president's second administration has slashed federal programmes - cuts that have been shepherded by Musk, the world's richest man and a close Trump ally.
"This really matters," said canvasser Ronneisha Mallet. "People aren't looking at the bigger picture. People just think this is just a local election. But it goes all the way to the White House."
The 23-year-old was out knocking doors in a quiet residential area on the outskirts of Milwaukee on Monday, a day before voters were set to cast their ballots.
She was here with Bloc - Black Leaders Organising for Communities - encouraging people to vote.
Conor Gunar said he was a "big fan" of Musk
These kinds of special elections typically see low voter turnout. But Musk's involvement has supercharged emotions on all sides.
Groups like Bloc put in extra time to engage with voters.
Not everyone opened their front door on Monday, but some of those who did told Ms Mallet they had already voted. By Monday, some 644,000 people had cast ballots early, according to the Wisconsin Elections Commission.
"I hate Musk! I hate his guts!" Peggy, standing at her door, said. She didn't want to give the BBC her full name, but described herself as an independent voter who has soured on the Republican Party.
"I think Musk bought the presidency," she said, in reference to the quarter-of-a-billion dollars that Musk spent in support of Trump's presidential campaign.
"And so I think he's trying to buy the election here," Peggy continued. "And I am hoping that people are starting to wake up."
Democrats, too, have rallied deep-pocketed donors in support of Crawford. Along with Soros, Illinois Governor JB Pritzker and LinkedIn founder Reid Hoffman have reportedly contributed large sums. But their names haven't inspired the same vitriol as Musk's.
Andrew Blum
Canvassers from Bloc - Black Leaders Organising for Communities
Another resident - who gave his name as Palman - said he had already voted, in part as a reaction to Musk.
"When you're a billionaire, you don't spend money for no reason," he said. "He's just spending it with purpose."
On Sunday, Musk hosted a rally where he handed out two $1m cheques to voters who had signed a petition to stop "activist" judges who might disrupt Trump's plans.
We drove about a half-hour outside of Milwaukee to Waukesha - a swing county that President Trump won. Around 100 people were gathered at the Dockhaus brewery and restaurant overlooking a baseball park, where Schimel made a campaign stop.
Conor Gunar was wearing a red shirt with Musk's name on it.
"I'm a big fan," he said, clutching his beer. "He is doing a fantastic job with Doge."
"Why not?" he added when asked about Musk's involvement in the race. "Democrats have people like George Soros and JB Pritzker; why can't we have billionaires?"
Scarlett Johnson said a Musk event at the weekend was "great fun"
Another Schimel supporter, Scarlett Johnson, agreed.
She was at Musk's town hall-style event over the weekend, which she described as "great fun".
But she said she also understood the criticism.
"Look, I think it would be great if no billionaires were involved at all, but if they're going to be as they have for Democrats, it's only fair they're involved for Republicans."
On the left, strategists see a glimmer of light as they search for a clear political strategy.
Drive down the roads, and you can see billboards plastered in cities like Green Bay and Madison that read "don't let Elon buy our court" and depict the SpaceX and Tesla boss as a puppeteer.
Switch on the TV and you'll see attack ads that say: "Elon Musk is out of control."
Watch: Elon Musk gives two $1 million cheques to Wisconsin voters
Going after Musk instead of Trump seems to be a strategic option for Democrats.
A poll by Marquette Law School suggests Musk is viewed unfavorably by 53% of registered voters here.
Driving in his car across rural Wisconsin, Ben Wickler, chairman of the Wisconsin Democratic Party, told the BBC that if Crawford could beat Schimel, "there'll be a very clear kind of game plan for how to fight back against the world's richest man trying to destroy American democracy".
Allison Prasch, a professor at the University of Wisconsin-Madison who specialises in US political rhetoric, said this race was a strategy test for both sides.
"We know that Wisconsin, up to the very end of the presidential cycle, was very close," she said, noting that some cities such as Milwaukee and Madison unexpectedly swung towards Trump and helped deliver him the state's electoral college votes.
"What happens in Wisconsin [now] is going to tell us a lot about what's going to happen, not just in 2026 but in 2028."
Musk's critics say he has practical reasons to care about the Wisconsin race.
They point to an ongoing case involving Tesla, Musk's electric vehicle company, that could head to the state's supreme court in the future.
The billionaire is suing because Wisconsin bans car manufacturers from owning dealerships, but Tesla's business model involves running its own showrooms.
The BBC has contacted Musk's America PAC for comment.
Wisconsin Republican strategist Matt Terrill said Musk was allowed to donate to campaigns for things he personally cared about, like any other citizen might - including the Democratic donors heavily backing Crawford.
"Musk has obviously got his views from a political standpoint of what he as an American citizen wants to see happen, not just as someone who's a part of the Trump administration," said Terrill.
The result won't just be a referendum on Trump's presidency so far, but will test Musk's reputation as a kingmaker in American politics.