Ross Douthat: 2020 will not be decisive

An election is supposed to be a reality check. It promises the finality of decision, in which the back-and-forth of political argument gives way to the undeniability of a particular outcome on a particular day.Scoff at the possibility that Donald Trump could ever be the Republican nominee (as I did, once upon a time), and a succession of primaries will reveal the hollowness of your supposed expertise. Insist on the certainty of polling or political science, or some variable (rally size, yard sig