In the past four weeks, Elon Musk has offered a peace plan for Russia and Ukraine that outraged Ukrainian officials. He has posted a tweet about Iranian internet access that exposed government protesters to a phishing scheme. He has also suggested in a newspaper interview that China could be appeased if it were given partial control of Taiwan. An official in Taipei demanded that he retract his suggestion. Musk has in recent months emerged as a new, chaotic actor on the stage of global politics. While plenty of billionaire executives like to tweet their two cents on world affairs, none...