The electric-car maker, the main source of the mercurial billionaire’s wealth, is relying on China to stay profitable as sales sink elsewhere.

In the first weeks of Donald Trump’s second term in office, Elon Musk has been busy seizing control of instruments of government power, causing many to wonder who is really in charge. “Elon Musk is President,” The Atlantic ’s Jonathan Lemire declared. “There has never been a private citizen like him.”