Elon Musk said he’s carrying out his threat to form a new political party after his fissure with President Trump, announcing on social media that he would form the America Party in response to the president’s sweeping new law.

Musk would need to overcome many hurdles to establish a third party. Similar efforts, including the late billionaire Ross Perot’s, haven’t lasted.

The billionaire and former Trump adviser suggested that if the domestic policy bill passed, he would swiftly form a new “America Party” and back primary challenges to Republicans.