A college psychology professor of mine liked to say that life was all about adjusting to loss.

He was clearly prepping me for Tuesday night’s debate.

George Pataki: exiled. Lindsey Graham: gone.

Their spots in the minor leagues were taken by Mike Huckabee, who once upon a time won the Iowa caucuses, and Chris Christie, who long ago represented the Republicans’ great hope for taking the White House back from the Democrats. Demoted and diminished, Huckabee and Christie stood in the lesser lineup as testaments to the cruelties of politics, which is another way of saying that they stood next to Bobby Jindal and Rick Santorum.

The major-leagues event shrank, with eight candidates where there had been 11 back in the glory days of Scott Walker. Do you remember Walker? And do you remember that he was briefly considered something of a front-runner, at least for a few weeks earlier this year?

So was Jeb Bush — more than briefly — and LAST year, Rand Paul appeared on the cover of Time and was ranked No. 1 on Politico’s annual list of visionaries transforming American politics. For Tuesday night’s debate, he remained in the major leagues, but at a far end of the stage, like a hard-luck mountaineer holding tight to a crumbling cliff, about to fall into the abyss, by which I mean the Christie-Huckabee-Jindal-Santorum crowd.

A classic old TV program was called “Queen for a Day.” The Republican primaries could be called “Front-Runner for a Day.” The turnover in leaders and the turns of fortune have been that plentiful.

And that confusing.

I’m adjusting to the loss of coherence in the political process. For all our analyses of Ben Carson’s lure as an outsider and his appeal to evangelical Christians, it still makes little sense that he’s done quite this well for quite this long, given his proclivity toward fantasy, both historical and personal, and his tenuous relationship with anything that might be considered an actual platform or a governing philosophy.

It doesn’t make a whole lot more sense that the Donald Trump phenomenon steams on and on.

He got a fresh burst of attention, as if he needed it, from a gig last weekend on “Saturday Night Live” that said everything about the erased line between politics and entertainment and about the way in which a public figure’s currency today is measured in the eyeballs he or she can draw, not the ideas he or she promotes. It’s a function of visibility, not integrity. Of clicks, not character.

I’m confident that most of the comedians, writers and producers of “Saturday Night Live,” along with most of the executives at NBC, aren’t Trump voters. Over drinks with friends, they probably bemoan his political ascendance, gaping at the country’s nutty trajectory.

But they readily gave him the microphone, and he reliably gave them their best ratings in years.

Success will almost always override ideology.

The Republican debates, more raptly watched than most people would have predicted at the outset, have affirmed the candidates as jesters — as performers in a profitable spectacle — and the candidates in turn have begun to behave like actors negotiating perks in their contracts and quibbling over the sizes of their trailers on set.

After they didn’t like the way that CNBC handled the Republican debate two weeks ago, they moved to assert control over when and how the camera would frame the lecterns and what sorts of visual images would be shown before and between snippets of the actual debate.

Trump loves to set the terms regarding his appearances, a mercurial diva who will entertain certain questions and questioners but not others.

I thought I’d made peace long ago with the magnitude of vanity and arrogance in politics, but then Trump, Ted Cruz, Carly Fiorina and the 2016 presidential campaign came along.

Even Carson, who was supposed to be the humble one, has been unmasked as something of an egomaniac, his biography aggrandized, his home decorated as a shrine to himself. Among the losses I grieve is the belief — or maybe it was just a wish — that a significant fraction of the candidates who talked of “public service” really meant it, and saw politics as an act of generosity, not of self-validation.

Tuesday night’s debate was the fourth meeting of the Republicans, but it felt more like the 40th, and that’s because these debates have not for the most part been debates. More so than usual, they’ve been oratorical beauty pageants. They’ve been invitations to preen.

Pity the poor orator. Pity the person who preens reluctantly, with obvious discomfort. Pity Bush, who isn’t finding the reception he banked on and isn’t looking at the outcome he dreamed of.

Talk about adjusting to loss.