The post-Trump GOP — which looks increasingly likely to begin Nov. 9 — will face the biggest crisis of identity in the party's century and a half of existence. An “autopsy” was ordered after the loss four years ago; this time, someone may need to check the dental records to make sure it’s still the party of Lincoln and Reagan.

Even in the event Donald Trump manages to upset Hillary Clinton, a possibility currently rated between 1 in 8 and 1 in 6 by the prognosticators at FiveThirtyEight.com, something will have to change among Republicans. That's because, whoever wins the election, this country looks set to remain more divided than it's been in decades, if not longer.

The most common refrain is the GOP will have to become less conservative in one way or another if it’s to have a chance of being a unifying force again. The opposite may be true, to hear the only conservative in the race tell it.

That of course isn't Trump. It's Evan McMullin , who aims to be the most consequential write-in candidate in U.S. presidential history.

McMullin is the former CIA operative and House GOP policy chief who's running as a #NeverTrump conservative. Recent opinion polls give him an outside chance of winning in Utah . But his influence this year probably won't come from pushing the election to Congress (in part because Trump looks incapable of doing his part by winning enough states to keep Clinton under 270 electoral votes).

No, if McMullin has an impact, it may come from reminding us why a conservatism focused on limiting and decentralizing power is ultimately our best hope of solving our differences. First, McMullin argues for transferring some power back to Congress from the executive branch. But he doesn’t stop there.

"There is too much power in Washington," McMullin said in an interview before his campaign event Monday night in Atlanta . "It leaves too much opportunity for corruption. It makes government unaccountable to the American people and less efficient."

So far, so familiar. Republicans have been pretty consistent about extolling the virtues of limiting centralized power — Trump’s “I alone can fix it” claims notwithstanding.

Then McMullin added this: “And it divides us.”

“One of the main reason this country is so divided,” he continued, “is so much power is in Washington. We have 330 million people fighting over decisions in one place that result in top-down solutions for the whole country. If Vermont wants to have a single-payer health-care system, and Utah wants to have more of a market-based system, so be it! Let them do that and govern themselves.

“And I think that can be the key to our unity as Americans, is if we respect each other’s ability to self-govern, and I just don’t see that right now.”

I doubt anyone else sees it, either. The mistaken belief on both the right and the left that each is just about to deliver the philosophical, or at least electoral, knock-out punch is part of the reason we’re forever hearing “this is the most important election of our lifetimes.” If power must be concentrated in D.C., with the most important decisions made there and applied to all, then those cries might prove true.

But if we need only agree on one crucial thing — that we need not agree on everything, because we can make 50 decisions on some of the most important issues instead of one — then we have a chance.