Joe Scarborough really hates it when people say his MSNBC morning show boosted Donald Trump's presidential candidacy during the Republican primary. All that frustration poured out Thursday morning when the former GOP congressman got into a heated argument with Weekly Standard editor Bill Kristol, who suggested "Morning Joe" enabled the eventual nominee early in the campaign.

"This show was really tough on Trump in late 2015 and early 2016," Kristol said, his remark dripping with sarcasm.

"Please don't come on my air and lie," Scarborough replied. And the fight was on.

SCARBOROUGH: I can't even believe you're doing this. I don't know why you're so bitter.
KRISTOL: I'm not bitter. I'm trying to say the Republicans — I'm trying to say the Republicans ...
SCARBOROUGH: You're practically crying! You're practically crying!
KRISTOL: I am upset about this election. That's right, Joe. 'Cuz you think it's amusing that Donald Trump is the nominee.

So it went for several minutes after Kristol re-opened an old wound. A few more highlights:

SCARBOROUGH: Early December 2015, we compared it to Germany 1933, what he was doing.
KRISTOL: Oh, that's ...
SCARBOROUGH: Really. We've got — you know ...
KRISTOL: And you treated him that way when he called in, is that right?
SCARBOROUGH: Well, yeah. We treated him tough.
KRISTOL: You treated him tough. You asked the most tough question. Look, we don't need to get into this. We agree on this now.
SCARBOROUGH: Well, no. It's too late. It's too late. You're bitter. You come on here practically crying. We've got it on tape.

Scarborough and co-host Mika Brzezinski were often criticized by their media peers during the primary for allegedly being too cozy with Trump, who frequently called in to their program and even thanked them for being "supporters" after his win in the New Hampshire primary in February. The label clearly made the hosts uncomfortable in the moment, and Trump quickly changed his description to "believers." But the comment reinforced an existing perception.

CNN's Dylan Byers reported a couple of days later that "in background discussions, NBC News and MSNBC journalists, reporters and staffers said there was widespread discomfort at the network over Scarborough's friendship with Trump and his increasingly favorable coverage of the candidate."

The next week, The Washington Post's Erik Wemple panned a Trump town hall moderated by Scarborough and Brzezinski, pointing to Trump's record of statements about women, minority groups, the disabled and others:

Any hour-long session with Donald Trump that doesn’t ask him about those obscenities is a puff session. Allowing this fellow to pronounce on entitlement reform, strategies on the Islamic State, campaign tactics, Iraq, Jeb Bush, health-care reform, gun rights, Supreme Court nominations and other such topics without grinding through an extensive accounting of his racism and bigotry is an outrage only sightly less egregious than the candidate's own.

Wemple's blog post fired up Scarborough, who responded by saying critics of his program's coverage are just jealous that he and Brzezinski had the foresight to treat Trump as a legitimate contender when others in the press considered him a sideshow.

"I do understand there's a great deal of resentment out there," Scarborough said. "We are analysts; our job is to analyze. And Mika and I certainly understand you're really angry because we called this first. We understand you're humiliated because this is your job. And while you were saying Donald Trump was a joke, we were saying that Donald Trump was actually going to have an impact on this race."

In any case, Trump's relationship with "Morning Joe" quickly deteriorated after that. When Trump claimed not to "know anything about David Duke" in an interview on CNN in late February, declining to disavow the former Ku Klux Klan leader's support, Scarborough called the candidate's remark "disqualifying."

Donald Trump was once seen as being a little too cozy with "Morning Joe" hosts Joe Scarborough and Mika Brzezinski. Not any more. (Peter Stevenson/The Washington Post)

More recently, Scarborough and Brzezinski have been among Trump's fiercest media critics — and favorite targets for ridicule.

No one would mistake Scarborough and Brzezinski for Trump supporters these days, but Kristol clearly has not forgotten about their previous coverage. And Scarborough has not forgotten that criticism of that coverage makes him angry.

The Fix’s Aaron Blake breaks down the key moments of the third presidential debate on Oct. 19 between Hillary Clinton and Donald Trump. (Bastien Inzaurralde/The Washington Post)