The political class exacts little or no penalty on politicians, commentators, and activists who back a government intervention, particularly in the foreign policy realm, that goes disastrously wrong. McCain not only championed the war in Iraq but called Obama’s 2011 foray into Libya “both right and necessary.” He is forever advocating further troop surges in Afghanistan, the arming of various rebels in Syria and elsewhere, sketchy new additions to the North Atlantic Treaty Organization, and economic sanctions against whichever country he’s not quite ready to bomb. Not only are these recommendations frequently wrong, they are typically delivered in the highest moral dudgeon.

Trump has been an explicit critic of this promiscuous interventionism, saying such non-McCainite things about Afghanistan as “I want to find out why we’ve been there for 17 years.”

McCain’s political cynicism and insincerity, too, made Trumpism more attractive. In 2006 and 2013, the Arizona senator was the GOP point man on bipartisan efforts to craft comprehensive immigration reform. But whenever he was up for a tough election—against Obama in 2008, or against immigration hawk J.D. Hayworth for Senate in 2010—McCain pandered grossly to the base, rejecting bills he’d previously co-sponsored and vowing to “complete the danged fence.”