How divided have Americans become? When it comes to the two-party war, the differences could not be starker. Pew Research Center has reported that 55 percent of Democrats are “afraid” of the Republican Party and nearly half of Republicans are similarly fearful of Democrats. These survey results were published in June 2016—before Donald Trump was elected. Since then, of course, the enmity has increased. Trump's genius for stirring up discord is one reason, but only one: The ingredients of all-out political warfare have been simmering for many years, as each of the two parties has discarded the old-fashioned ideal of the “big tent” and enacted its own purifying rituals.