Republican presidential nominee Donald Trump during the third day of the Republican National Convention on Wednesday, July 20, 2016. (Jabin Botsford/The Washington Post)

CLEVELAND — For every Gov. John Kasich (who stayed away) or Sen. Ted Cruz (who came but did not endorse), there are a dozen Republican bigwigs in Cleveland who believe Donald Trump is unfit to be president but have endorsed him anyway.

How do they live with their decisions? These are politicians who are privately persuaded that Trump is too ignorant, too narcissistic, too potentially tyrannical, not genuinely conservative—or some combination of the above. So how to justify an endorsement?

I’ve had a chance to ask some of them on the sidelines of the convention this week. The most common answer is: We know Hillary Clinton will be terrible, whereas we might be wrong about Trump, so let’s take a chance.

But I’ve also heard: Donald Trump doesn’t care about policy or understand how it is shaped, so Speaker Paul Ryan and Majority Leader Mitch McConnell will set the agenda. In this fantasy, Trump would be satisfied with the trappings of the office, while a Republican Congress finally gets to work its will.

Then there’s the vision of Trump as empty vessel: Donald Trump has no fixed beliefs, but he will surround himself with genuine conservatives who will gradually shape his ideology.

Or this variation: Donald Trump has despotic tendencies, but the people around him in the White House and the Cabinet will rein in his worst instincts.

If that fails, there is this: If necessary he can be impeached.

And finally, from an ardent free-trader whom I pressed about supporting someone who would impose tariffs, spark trade wars and potentially trigger a global depression: It’s okay — he can’t win.

I’m sure it is more difficult politically than most of us can imagine for a Republican to stay aloof from the Republican candidate for president. The one genuine, uniting sentiment in the party this year is a visceral, almost frenzied hatred of Hillary Clinton. One congressman who has yet to endorse told me the blowback from constituents is intense and constant.

But I’m also pretty sure that most of these people know the stories they tell themselves are fiction. Donald Trump is not going to win the most powerful job in the world only to let some uncharismatic wannabes down Pennsylvania Avenue dictate his agenda. A man who wins the presidency by taking advice only from himself, and maybe his adult children, is not going to suddenly learn to govern by committee. As to impeachment: it is beyond far-fetched to think that Republican legislators who cannot stand up to Trump while he is a private citizen will find new courage to resist him once he has the power of the presidency.

Which leaves the final hope: He can’t win.

Well, maybe so. We all remember hearing that he could never be nominated. But even if the candidacy proves a disaster, how sad it is to hear supposed leaders counting on voters to show the fortitude that they cannot muster themselves.