Elon Musk, President Donald Trump‘s billionaire backer, has funneled more than $2.6 million and counting into a Wisconsin Supreme Court election that could decide on a case involving Tesla, his electric vehicle company.

The contest that will decide the political tilt of the swing state’s highest court is likely to be the most expensive state court race in U.S. history.

Wisconsin will hold a special election to replace a retiring liberal justice on the state Supreme Court. It’s set to be the most expensive state court race in U.S. history—breaking the record for a different Wisconsin Supreme Court seat in 2023,