Mr. Musk has built a constellation of like-minded heads of state — including Argentina’s Javier Milei and India’s Narendra Modi — to push his own politics and expand his business empire.

© Cristiana Couceiro

Donald Trump’s social media platform has outdistanced similar conservative sites such as Parler and Gettr, even as it lags far behind X and others.

© John Minchillo/Associated Press