To me, the most surprising part of Trumps nomination which is to say, the part I think I got wrongest is that Trump won the nomination despite having all types of deviations from conservative orthodoxy. He seemed wobbly on all parts of Reagans three-legged stool: economic policy (he largely opposes free trade and once advocated for a wealth tax and single-payer health care), social policy (consider his constant flip-flopping over abortion) and foreign policy (he openly mocked the Bush administrations handling of the Iraq War, which is still fairly popular among Republicans).
Previous insurgent Republicans, such as the tea party candidates of 2010 and 2012, had run both as anti-establishment candidates and as more conservative than their rivals. Trump kept the anti-establishment branding, although this was also a selling point for Cruz, who often ran neck-and-neck with Trump among voters who said they felt betrayed by the Republican Party in exit polls.
But whereas Cruz offered a mix of anti-establishmentism and movement conservatism and whereas Marco Rubio offered movement conservatism plus a strong claim to electability Trumps main differentiator was to double-down on cultural grievance: grievances against immigrants, against Muslims, against political correctness, against the media, and sometimes against blacks and women. And the strategy worked. Its a point in favor of those who see politics as being governed by cultural identity a matter of seeking out ones tribe and fitting in with it as opposed to carefully calibrating ones position on a left-right spectrum.
Whats much harder to say is whether Trump is a one-off someone who defied the odds because a lot of things broke in his favor, and whose success will be hard to repeat or if he signifies a fundamental change in American politics. Trump hasnt brought a wave of tea party candidates success in gubernatorial and senate primaries; in Indiana, in fact, the same voters who elected Trump also gave establishment-friendly U.S. Representative Todd Young a 67-33 victory in the states senate primary over the tea-party-aligned Marlin Stutzman. And the Democrats have had a relatively orderly nomination process. Still, its hard to imagine that American politics will ever be quite the same after this.