Rich Lowry: He's a Republican Now

Donald Trump, the erstwhile Democrat, independent and member of the Reform Party, finally has a fixed partisan identity.

The president may be besieged, unpopular and prone to lashing out self-destructively, but all of this cements his bond to his party rather than erodes it. Commentators who ask wishfully and plaintively, "When will Republicans dump Trump and save themselves?" are missing the point: Trump's weakness makes him more Republican than ever before.

It was possible to imagine Trump, with a head of steam after his upset victory in November, cowing swamp-dwelling Republicans and wooing...