A group backed by billionaire Elon Musk is behind a new set of deceptive attack ads and text messages targeting voters just weeks ahead of the election for a seat on Wisconsin’s Supreme Court.

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.

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.