These days, Tesla investors would probably like to be thinking about EV sales, robo-taxis, or anything else besides politics.

Before we assess the eternally unrealized dream of a potent third party in American politics, let’s consider the specific, recently emergent dream of one specific man: Elon Musk.

Instead of the quadrennial dream of No Labels, in which high-minded donors put up the money for an imaginary white knight who never materializes, we may get the “America Party,” in which the world’s ...