Tesla CEO Elon Musk and President Donald Trump appear to be in the kind of chaotic relationship that social media lives to warn you about. First the two seemed to be enjoying a business alliance-turned-bromance when Musk was invited to become a special government employee in January and spearhead the Department of Government Efficiency (DOGE).

Musk attacked Trump directly over his signature spending bill for the first time Thursday, sparking an explosive back-and-forth.

Elon Musk’s bitter falling-out with President Trump could be costly for Tesla. As long as he is persona non grata in the Trump administration, Mr. Musk, the chief executive of Tesla, will struggle to persuade Republicans not to gut climate policies worth billions of dollars to the electric car and battery company.