WASHINGTON — Senate Foreign Relations Committee Chairman Bob Corker (R-Tenn.) capped off a day of volleys with President Trump by telling the New York Times that the commander in chief is slinging threats in a way that could put the country “on the path to World War III.”

“I know he has hurt, in several instances, he’s hurt us as it related to negotiations that were underway by tweeting things out,” Corker told the paper without going into specifics.

Trump tweeted this morning: “Senator Bob Corker ‘begged’ me to endorse him for re-election in Tennessee. I said ‘NO’ and he dropped out (said he could not win without my endorsement). He also wanted to be Secretary of State, I said ‘NO THANKS.’ He is also largely responsible for the horrendous Iran Deal! Hence, I would fully expect Corker to be a negative voice and stand in the way of our great agenda. Didn’t have the guts to run!”

Corker fired back, garnering 118,000 retweets and 326,000 likes as of midnight: “It’s a shame the White House has become an adult day care center. Someone obviously missed their shift this morning.”

Trump later tweeted, “Bob Corker gave us the Iran Deal, & that’s about it. We need HealthCare, we need Tax Cuts/Reform, we need people that can get the job done!”

Corker announced Sept. 26 that he wouldn’t seek a third term next year, adding at the time that “the most important public service I have to offer our country could well occur over the next 15 months, and I want to be able to do that as thoughtfully and independently as I did the first 10 years and nine months of my Senate career.”

In a phone interview today with the NYT, Corker said the presidency was being treated like “a reality show” with Trump acting “like he’s doing ‘The Apprentice’ or something.”

“He concerns me,” Corker said. “He would have to concern anyone who cares about our nation.”

The senator said the “vast majority” of the Republican caucus understands “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.”

Corker said Trump’s account of his re-election decision was false; as he described the exchange, the president urged him to run again and promised to endorse the Tennessee senator if he did, but he told Trump it was “just not in the cards.”

“I don’t know why the president tweets out things that are not true,” he said. “You know he does it, everyone knows he does it, but he does.”

The chairman told the NYT that he means Trump “no harm,” but said he knows “for a fact that every single day at the White House it’s a situation of trying to contain him.”

If Trump does get rid of Rex Tillerson, a new secretary of State nominee would have to clear Corker’s committee. Decertification of the Iran nuclear deal would also send the issue back to Congress for sanctions review and possible restoration, and straight into Corker’s court.

In August, Corker told a Rotary Club that Trump “has not yet been able to demonstrate the stability, nor some of the competence, that he needs to demonstrate in order for him to be successful” and “also recently has not demonstrated that he understands the character of this nation.”

Last week, Corker praised Tillerson, John Kelly and James Mattis as “people that help separate our country from chaos.”

“They work very well together to make sure the policies we put forth around the world are sound and coherent,” he he said. “There are other people within the administration that don’t. I hope they stay because they’re valuable to the national security of our nation.”