On Tuesday morning, Sen. Bob Corker (R-TN) appeared on a number of morning news shows to criticize President Trump for his reckless tweets, his handling of the North Korea crisis, and his efforts to divide the country, among other issues.

During one particularly notable exchange on the Today Show, the chairman of the Senate Committee on Foreign Relations — who has become a sharp Trump critic since he announced in late September that he won’t be seeking reelection to the U.S. Senate — refused to rule out that President of the United States poses a threat to national security.

“I think there are people around him that work in an effort to contain him,” Corker said, in reference to Defense Secretary Jim Mattis and Secretary of State Rex Tillerson. His dodge prompted the host to follow up by noting that Corker “seems to accept the the premise of the question.”

Corker replied by noting he worries Trump’s recklessness “could lead us into a world war.”

“I do think when you have the kind of issues we’re dealing with in North Korea, where we have a very unstable leader there, when you send out tweets into the region to raise tensions, when you kneecap — which is what he’s done, publicly — when you kneecap your secretary of state, whose diplomacy, you have to depend on to bring China to the table, to do the things that need to be done, back-channeling in some cases to North Korea — when you kneecap that effort, you move our country into a binary choice that could lead us into a world war,” he said.

WATCH: "Left to his own devices, do you think the president is a threat to national security?" @savannahguthrie asks @SenBobCorker pic.twitter.com/GxFFZvUTeU — TODAY (@TODAYshow) October 24, 2017

On Good Morning America, Corker said he has no second thoughts about responding to one of Trump’s reckless tweets earlier this month by tweeting, “It’s a shame the White House has become an adult care care center. Somebody obviously missed their shift this morning.”

It's a shame the White House has become an adult day care center. Someone obviously missed their shift this morning. — Senator Bob Corker (@SenBobCorker) October 8, 2017

“I would just like for him to leave it to the professionals for a while and see if we can do something that’s constructive for our country, the region, and the world,” Corker said.

Sen. Bob Corker doubles down on Trump critique; on North Korea "I would like him to leave it to the Professionals for a while" pic.twitter.com/ArgbRTxhnB — GeorgeStephanopoulos (@GStephanopoulos) October 24, 2017

And on CBS This Morning, Corker decried Trump’s efforts to divide the nation, citing his response to the violent white supremacist rally in Charlottesville in particular.


“Hopefully what presidents do is to try to bring the country together, to unify around common goals and not to debate our country if you will, and that has not happened, and I’m beginning to believe that it’s not going to happen, and I think that’s what President Bush, President Obama, many others have been concerned about,” Corker said. “It appears to be the governing model of this White House to purposely divide — that’s what happened after the Virginia incident. It’s to consolidate base, not to bring people together.”

“It appears to be the governing model of this White House to divide,” @SenBobCorker says https://t.co/hLUPlCpqdZ pic.twitter.com/3gqd8WjOHa — CBS News (@CBSNews) October 24, 2017

Trump — who regularly live-tweets morning TV news shows — quickly responded to Corker’s latest criticisms by attacking him on Twitter, claiming the senator who won his reelection campaign by 35 points in 2010 “couldn’t get elected dog catcher in Tennessee.”

Bob Corker, who helped President O give us the bad Iran Deal & couldn't get elected dog catcher in Tennessee, is now fighting Tax Cuts…. — Donald J. Trump (@realDonaldTrump) October 24, 2017

…Corker dropped out of the race in Tennesse when I refused to endorse him, and now is only negative on anything Trump. Look at his record! — Donald J. Trump (@realDonaldTrump) October 24, 2017

Corker shot back, calling Trump “utterly untruthful.”

Same untruths from an utterly untruthful president. #AlertTheDaycareStaff — Senator Bob Corker (@SenBobCorker) October 24, 2017

Trump — who also mocked Corker’s height on Twitter earlier this month — posted his latest attacks the day after First Lady Melania Trump launched a new anti-bullying effort. The First Lady’s communications director told reporters she doesn’t feel any need to reconcile her anti-bullying work with the fact her husband is one of the country’s most notorious bullies.

Trump’s latest tangle with Corker comes the day after he accused a Gold Star widow of lying about a condolence call in which she claimed Trump couldn’t remember her husband’s name and made inappropriate remarks, including telling her that her husband “knew what he was signing up for.”

UPDATE (10/24, 8:30 a.m.): Trump’s responded to Corker calling him “utterly untruthful” with yet another insult.

Isn't it sad that lightweight Senator Bob Corker, who couldn't get re-elected in the Great State of Tennessee, will now fight Tax Cuts plus! — Donald J. Trump (@realDonaldTrump) October 24, 2017

UPDATE II (10/24, 8:45 a.m.): During an interview with CNN conducted shortly after Trump posted tweets insulting him, Corker said he doesn’t understand “why [Trump] lowers himself to such a low, low standard, and debased our country in the way he does.”

He added that he regrets supporting Trump during the 2016 election.

“I would not do that again,” Corker said of his previous support for Trump. “I think he’s proven himself unable to rise to the occasion, and I think many of us, me included, have to tried to, you know, intervene, and I have had a private dinner and have been with him on multiple occasions to try and create some kind of aspirational approach, if you will, to the way that he conducts himself. I don’t think that that’s possible. He’s obviously not going to rise to the occasion as president.”

UPDATE III (10/24, 9:20 a.m.): Following Corker’s CNN interview, the president mocked his height for the second time in October.

Sen. Corker is the incompetent head of the Foreign Relations Committee, & look how poorly the U.S. has done. He doesn't have a clue as….. — Donald J. Trump (@realDonaldTrump) October 24, 2017