Sen. Bob CorkerRobert (Bob) Phillips CorkerPollster says Trump unlikely to face 'significant' primary challenge GOP gets used to saying 'no' to Trump Democrats introduce bill to rein in Trump on tariffs MORE (R-Tenn.) unloaded on President Trump during the course of multiple interviews Tuesday, accusing him of "debasing" the nation and predicting he's "not going to rise to the occasion as president."

In interviews on CNN and ABC, Corker refused to say whether he trusts Trump with the nuclear codes. He also said world leaders don’t trust the president because they are “aware that much of what he says is untrue.”

“He purposely is breaking down relationships we have around the world that have been useful to our nation, but I think at the end of the day, when his term is over, I think the debasing of our nation, the constant non-truth-telling, the name calling … the debasement of our nation will be what he will be remembered most for, and that's regretful,” Corker said on CNN. 

“And it affects young people,” Corker continued. “I mean, we have young people who for the first time are, you know, watching a president stating, you know, absolute non-truths, nonstop, personalizing things in the way that he does, and it's very sad for our nation.”

Trump and Corker reignited their feud just hours before the president was set to meet with Republican senators on Capitol Hill about tax reform. The legislative effort is likely the GOP’s last chance to pass major legislation during Trump’s first year in office.

In an interview on ABC’s “Good Morning America,” Corker said the president is so toxic within Republican circles that his involvement in the tax-reform debate would make it harder to pass legislation.

Trump retaliated over Twitter, saying that Corker is retiring at the end of his term because he "couldn’t get elected dog catcher in Tennessee." He accused the senator of being one of the architects of the Obama administration’s nuclear deal with Iran, an allegation Corker says is an outright falsehood.

“We grew up in our family not using the [liar] word, okay, but yeah, just, I mean, they're provable untruths. Provable,” Corker said. “So on the Iran deal, everybody knows the role I played there and they're working with me, interestingly, right now, on tax reform.”

“I don't know why he lowers himself to such a low, low standard and debases our country in the way he does but he does… but it's unfortunate our nation finds itself in this place,” Corker added.

The Tennessee Republican has cut loose with his unvarnished feelings about Trump since announcing last month that he will not seek reelection.

Had he run, Corker would likely have faced a primary challenger from the right. Former White House chief strategist Stephen Bannon is recruiting challengers to nearly all the GOP’s incumbents, and Corker was high on his target list.

But while Corker has criticized Trump in the past, at one point comparing the White House to an adult day care center, the attacks he launched Tuesday were the most personal to date. 

“I've intervened, had private dinner, been with him on multiple occasions to try to create some kind of aspirational approach, if you will, to the way that he conducts himself, but I don't think that that's possible, and he's obviously not going to rise to the occasion as president,” Corker said.

When asked if he regrets supporting Trump’s 2016 presidential bid, Corker responded that there’s “no way” he’d ever support the president for an election again.

He said Trump is “absolutely not” a role model for young children, and refused to say whether he trusts the president with the nuclear codes.

“I expressed concerns a few weeks ago about his leadership and just his stability and the lack of desire to be competent on issues and understand and, you know, nothing has changed,” Corker said.