About half a dozen times in the past few weeks I have been taken aside by a 20-something who’s looking for reassurance that the republic will not end. There has never been any campaign like this in the history of the nation, they say, and they know this is true because they’ve read it everywhere. “We have officially hit a new low in political discourse,” declared Stephen Colbert (after Trump’s penis allusion on national television). Next, the Huffington Post warned, “Recent violence at Trump rallies marks a new low for American politics.” Not long after that, the Financial Times said:...