Musk used X—formerly Twitter—to help rebuild Trump's public image and support his presidential run. What happens if he turns it against the president?

For all the insults that Mr. Musk and Mr. Trump traded on Thursday, don’t be surprised if they make up again days from now. In the meantime, they both benefit.

An intense public feud erupted on Thursday between President Donald Trump and his one-time ally, billionaire Elon Musk, with an argument about Trump’s massive tax and domestic policy bill raging across social media and in the Oval Office.