The meddling of oligarchs and other monied interests in the fate of nations is not new. During the First World War, J. P. Morgan lent vast sums to the Allied powers; afterward, John D. Rockefeller, Jr., poured money into the fledgling League of Nations. The investor George Soros’s Open Society Foundations underwrote civil-society reform in post-Soviet Europe, and the casino mogul Sheldon Adelson funded right-wing media in Israel, as part of his support of Benjamin Netanyahu.

But Musk’s influence is more brazen and expansive. There is little precedent for a civilian’s becoming the arbiter of a war between nations in such a granular way, or for the degree of dependency that the U.S. now has on Musk in a variety of fields, from the future of energy and transportation to the exploration of space. SpaceX is currently the sole means by which NASA transports crew from U.S. soil into space, a situation that will persist for at least another year. The government’s plan to move the auto industry toward electric cars requires increasing access to charging stations along America’s highways. But this rests on the actions of another Musk enterprise, Tesla. The automaker has seeded so much of the country with its proprietary charging stations that the Biden Administration relaxed an early push for a universal charging standard disliked by Musk. His stations are eligible for billions of dollars in subsidies, so long as Tesla makes them compatible with the other charging standard.

In the past twenty years, against a backdrop of crumbling infrastructure and declining trust in institutions, Musk has sought out business opportunities in crucial areas where, after decades of privatization, the state has receded. The government is now reliant on him, but struggles to respond to his risk-taking, brinkmanship, and caprice. Current and former officials from NASA, the Department of Defense, the Department of Transportation, the Federal Aviation Administration, and the Occupational Safety and Health Administration told me that Musk’s influence had become inescapable in their work, and several of them said that they now treat him like a sort of unelected official. One Pentagon spokesman said that he was keeping Musk apprised of my inquiries about his role in Ukraine and would grant an interview with an official about the matter only with Musk’s permission. “We’ll talk to you if Elon wants us to,” he told me. In a podcast interview last year, Musk was asked whether he has more influence than the American government. He replied immediately, “In some ways.” Reid Hoffman told me that Musk’s attitude is “like Louis XIV: ‘L’état, c’est moi.’ ”

Musk’s power continues to grow. His takeover of Twitter, which he has rebranded “X,” gives him a critical forum for political discourse ahead of the next Presidential election. He recently launched an artificial-intelligence company, a move that follows years of involvement in the technology. Musk has become a hyper-exposed pop-culture figure, and his sharp turns from altruistic to vainglorious, strategic to impulsive, have been the subject of innumerable articles and at least seven major books, including a forthcoming biography by Walter Isaacson. But the nature and the scope of his power are less widely understood.