Musk used X to boost Trump. Now he’s wielding it against him.

For almost a year, Elon Musk marshaled the full force of X, his $45 billion social media platform, to boost Donald Trump’s political fortunes and second presidency. As he two men publicly fought in a flurry of furious online posts, Musk revealed X to be a double-edged sword. Musk spent hours firing off mocking memes, curt put-downs and explosive allegations to his 220 million followers, just as he did during Trump’s candidacy and as a member of his administration. Only this time, the target was Trump himself, not the president’s critics. The attack deployed tactics familiar from Musk’s many previous online battles. He dredged up old Trump tweets to suggest hypocrisy. He amplified posts from others critical of Trump. He accused the president of “an obvious lie” about the cause of their falling-out and blasted him for “ingratitude” for Musk’s political support, claiming that “without me, Trump would have lost the election.” As President Trump lobbed disparaging posts back from his own social media platform, Truth Social, Musk also turned to a tactic he has used against others who have crossed him: insinuations of personal scandal.