Wisconsin voters began casting ballots Tuesday in a state Supreme Court election that has become a proxy for the nation's political battles while attracting a massive amount of spending, led by groups affiliated with Elon Musk and other billionaires.

Wisconsin voters are casting the first ballots in a pivotal state Supreme Court race that will determine whether liberal or conservative justices control the highest court in the crucial presidential battleground.

With money pouring in from billionaires such as Elon Musk and George Soros, spending in the Wisconsin Supreme Court race could top $100 million.