After designing a hyperloop to vault travellers from Los Angeles to San Francisco in thirty-five minutes, establishing SpaceX so that humans can colonize other planets, and building a satellite-powered Internet system, Starlink, that has played a role in the war between Russia and Ukraine, Elon Musk has turned his attention to the U.S.-Mexico border. Last week, he visited Eagle Pass, Texas, for a firsthand look at the unfolding migration crisis, and streamed it live on his social-media platform, X (formerly known as Twitter), so that his hundred and fifty million followers could “see what’s really going on.” In an e-mail, Musk’s most recent biographer Walter Isaacson told me that the visit was another example of the billionaire’s “epic-hero complex”: Musk’s confidence that his attention w...