What is an American? That is the question that powered U.S. Sen. Eric Schmitt’s recent speech — a hodgepodge of contradictions, racism, and antisemitic tropes — at the National Conservatism Conference in Washington. The Missouri Republican wallowed in the kind of unabashed defense of Christian nationalism and white supremacy that, not too long ago, you would have turned to history books for, not C-SPAN. Yet, here we are. “We Americans are the sons and daughters of the Christian pilgrims that poured out from Europe’s shores to baptize a new world in their ancient faith,” Schmitt said. Period. No others need...