(CNN) From long before he took office, President Donald Trump has touted loyalty -- his to others, and others' to himself -- as a prize virtue.

It's at least half true.

Trump reiterated his philosophy on the matter a few years ago: "I'm loyal to people who've done good work for me."

"Good work" is, of course, a subjective means of measuring one's service to Trump. But it's a telling line mostly because of the subtext, which suggests Trump is indeed willing to repay subordinates who advance his interests with loyalty -- but only up to a point. When the "good work" ends or hits a snag, as we've seen over the past seven months and during the campaign before that, Trump's backing tends to do the same.

On this question, the story of Trump and his infamous McCarthyite mentor Roy Cohn is one case to consider. Here a few more timely snubs.

Mitch McConnell, interrupted?

The President's recent treatment of Senate Majority Leader Mitch McConnell, who narrowly failed to deliver the needed GOP votes to repeal Obamacare, is the most immediate illustration of Trump's fickle fealty.

In fairness, McConnell helped load himself into the barrel when he criticized Trump, albeit mildly, during a Monday speech to a Rotary Club in Kentucky.

"Our new President, of course, has not been in this line of work before," McConnell said. As it applies to the legislative process, he added: "I think (Trump) had excessive expectations about how quickly things happen in the democratic process."

The nuance there, that cautious caveat, did not land well with the White House. Trump has now spent the better part of the week assailing the top Senate Republican on Twitter and in remarks to reporters during what's been a news-making vacation at his golf club in Bedminster, New Jersey.

On Thursday, he pointedly refused to back McConnell, suggesting what remains of his faith in the majority leader will turn on future performance.

"I'll tell you what, if he doesn't get repeal and replace done, and if he doesn't get taxes done, meaning cuts and reform, and if he doesn't get a very easy one to get done, infrastructure, he doesn't get them done, then you can ask me" again if McConnell should give up his post, Trump said.

GOP senators have rallied around their colleague from Kentucky, mostly expressing their support, appropriately enough, on Twitter. Absent from those messages, so far, is the lengths to which McConnell went in support of Trump during the 2016 general election. Most notably, according to The Washington Post , McConnell balked at going public with a bipartisan statement when presented by Obama administration officials with intelligence community evidence of Russian meddling. He also threw his political body in front of President Barack Obama's Supreme Court nominee for more than a year, withstanding a fair amount of criticism, but keeping the seat warm for his new President. Trump's appointment of Neil Gorsuch as a Supreme Court Justice has been the legacy highlight of his tenure so far. On those counts, McConnell did good work for Trump.

Reince Priebus, swatted away

JUST WATCHED Reince Priebus' interview with Wolf (full) Replay More Videos ... MUST WATCH Reince Priebus' interview with Wolf (full) 15:32

Trump and Priebus, then the Republican National Committee boss, had an up-and-down relationship during the 2016 primaries. Despite leading in the GOP polls for months before the first ballot was cast, the party establishment (and many in the media) doubted Trump's viability, and whether he could sustain his popularity, once the contests kicked off.

Priebus, though, was clear on Trump's potential -- either to win or damage the eventual nominee's chances in November by going a third party route. There was drama over a loyalty pledge, which Trump signed, then waffled on, but ultimately honored, if only because his frontrunner status rarely wavered.

Whatever his misgivings, Priebus never intervened and eventually (technically) joined Trump's inner circle. His bald-faced backing cleared the way for other Republicans climb aboard.

Now, though, he is gone. Ousted in July after the Obamcare repeal effort failed, his inglorious run as White House chief of staff, fly-swatting and all, was the shortest -- ever

Chris Christie, sidelined

JUST WATCHED Donald Trump rips Chris Christie over Oreos Replay More Videos ... MUST WATCH Donald Trump rips Chris Christie over Oreos 00:52

New Jersey Gov. Chris Christie wasn't always quite so unpopular in his home state. His decline began well before he left the Republican presidential primary last year, but it's hard to imagine his decision to immediately throw his allegiance to Trump did much to reverse the slide.

Christie backed Trump before it was perceived as a political imperative. His precise motives in endorsing Trump are still not entirely clear. The theories range from vengeance against other more mainstream candidates like Florida Sen. Marco Rubio to strategic angling for future employment, or some combination of those and more.

In any event, Christie's loyalty was rewarded first with mocking. Trump made a joke of the governor's weight during a rally in New Jersey last May, then after winning the election, quickly sidelined Christie from the transition team. Why? The reasoning was never made entirely clear, but there are theories , some of which are centered on the fact that Christie at one point put Trump's son-in-law's father behind bars. Christie now remains in New Jersey, sometimes on its beaches , and without a White House job.

Jeff Sessions, what did you do?

JUST WATCHED President continues public attacks on Sessions Replay More Videos ... MUST WATCH President continues public attacks on Sessions 03:28

The attorney general, before he was attorney general, was a US senator from Alabama. He was also the first active member of that august body to endorse Trump during the GOP primary. When the "Access Hollywood" tape threatened to upend Trump's campaign, and some Republicans began to make for the exits, Sessions stood firm: "This thing is overblown," he told Fox News. "Everybody knows that Trump likes women."

After being elected, Trump nominated his most high-profile Washington loyalist to run the Justice Department. And there he remains -- if only just! Sessions' decision to recuse himself from a role in any investigation into the Trump campaign rankled the President. Big league. When the deputy attorney general named a special counsel to lead the Russia probe, after Trump fired FBI director James Comey, the situation really deteriorated.

As with McConnell, Trump didn't hesitate to air his ire on social media and in a memorably caustic interview with The New York Times.

"So why aren't the Committees and investigators, and of course our beleaguered A.G., looking into Crooked Hillarys crimes & Russia relations?", Trump, in his role as pundit-in-chief, tweeted on the morning of July 24.

So why aren't the Committees and investigators, and of course our beleaguered A.G., looking into Crooked Hillarys crimes & Russia relations? — Donald J. Trump (@realDonaldTrump) July 24, 2017

Sessions has managed to hang on mostly because he refused to resign and his old friends in the Senate made it clear Trump would not be able to quickly install a replacement if Sessions was fired.

Asked this week about their relationship, Trump offered a bright, shining endorsement.

"It is what it is," he said with a shrug . "It's fine."

For now.