It has largely slipped under the radar screens of partisan hatred in Washington, but has anyone noticed that in the last couple of months Donald Trump has become . . . a Democrat? Of course, for most of his life, Trump was a Democrat, a faithful fundraiser for Chuck Schumer and Hilary Clinton, and comfortably liberal in most of his positions. But once he decided to run for president as a Republican, he underwent a total transformation, becoming an arch-conservative. And during his first year in office, he governed like a conservative Republican, slashing taxes and regulations, appointing conservative judges,...