So to catalog my wrongness: I overestimated the real commitment of both factions’ leaders to their stated principles and favored policies. (Even though I didn’t agree with many of those policies myself, I assumed from the party’s longstanding resistance to change that someone did!) I overestimated their ability to put those principles ahead of personal resentments. And yes, since to acquiesce to Donald Trump as the Republican nominee is to gamble recklessly with the party’s responsibilities to the republic, I overestimated their basic sense of honor.

Of course none of this means that the surrendering Republicans’ calculations are all wrong. It is possible that a dishonorable, cowardly, unprincipled course will yield the result that many in both G.O.P. factions clearly crave: Trump defeated in the general election, his ideas left without a champion, and then a reversion to the party’s status quo ante, to the comforts of a tactically narrow “wacko birds versus RINOs” family feud.

But then again it’s possible that the establishment and the Tea Party are more like Byzantium and Sassanid Persia in the seventh century A.D., and Trumpism is the Arab-Muslim invasion that put an end to their long-running rivalry, destroyed the Sassanid Dynasty outright, and ushered in a very different age.