The feud reignited on Monday when Musk, who spent hundreds of millions on Trump's re-election, renewed his criticism of Trump's tax-cut and spending bill, which would eliminate subsidies for electric vehicle purchases that have benefited Tesla, the leading U.S. EV maker. That bill passed the Senate by a narrow margin midday Tuesday.

"If this insane spending bill passes, the America Party will be formed the next day," Musk wrote in an X post on Monday.