The degree to which Donald Trump and Elon Musk’s interests are intertwined is unprecedented—and ultimately unsustainable.

The Biden White House explained the snub by noting that the automakers that had been invited were the nation’s three largest employers of the United Auto Workers, a powerful union, and it suggested that the administration would find other ways to partner Tesla. (Union animus towards electric vehicles later became a problem for Mr Biden.)

After labeling Social Security “a Ponzi scheme,” Elon Musk’s offensive against the social-insurance program took another aggressive turn.