After the dust cleared from a Twitter brawl in which President Trump accused him of lacking "guts" and he compared the White House to an "adult day care center," Republican Sen. Bob Corker told The New York Times he believes Trump is out of control, and dangerous:

"He concerns me. He would have to concern anyone who cares about our nation."

Corker refuted Trump's claims that he had begged for an endorsement for 2018 and backed out when he didn't receive one, saying Trump had actually urged him to run: "I don't know why the president tweets out things that are not true. You know he does it, everyone knows he does it, but he does," he said.

Key quotes

"I know for a fact that every single day at the White House, it's a situation of trying to contain him."

He acts "like he's doing 'The Apprentice' or something."

On how fellow GOP senators feel: "Look, except for a few people, the vast majority of our caucus understands what we're dealing with here... of course they understand the volatility that we're dealing with and the tremendous amount of work that it takes by people around him to keep him in the middle of the road."

"Look, except for a few people, the vast majority of our caucus understands what we're dealing with here... of course they understand the volatility that we're dealing with and the tremendous amount of work that it takes by people around him to keep him in the middle of the road." On Trump undermining Tillerson: "A lot of people think that there is some kind of 'good cop, bad cop' act underway, but that's just not true."

"A lot of people think that there is some kind of 'good cop, bad cop' act underway, but that's just not true." On Trump's tweets harming U.S. foreign policy: "I know he has hurt, in several instances, he's hurt us as it relates to negotiations that were underway by tweeting things out."

The Times' take: "In a 25-minute conversation, Mr. Corker, speaking carefully and purposefully, seemed to almost find cathartic satisfaction by portraying Mr. Trump in terms that most senior Republicans use only in private."

Why it matters: Corker remains influential, and his breaking from Trump so publicly could lead others to speak out. Perhaps more significantly, the retiring Senator still holds a vote until Jan. 2019 in a Senate the Republicans control by a two-vote margin. He's highly skeptical of Trump's tax plan, and may be tough to get onside on other key issues.