A Top Republican Says President Trump Could Lead the U.S. Into World War III

Tennessee Republican Sen. Bob Corker escalated his war of words with President Donald Trump late Sunday, expressing concern that Trump’s temperament could lead the United States into an actual war — perhaps even World War III.

“I know for a fact that every single day at the White House, it”s a situation of trying to contain him,” Corker told the New York Times. “I don’t think he appreciates that when the President of the United States speaks and says the things that he does, the impact that it has around the world, especially in the region that he’s addressing. And so, yeah, it’s concerning to me.”

Corker, the Chairman of the Senate Foreign Relations Committee who recently announced he would not seek reelection next year, also told the Times that Trump has adversely impacted international diplomacy with his Twitter feed, and that every Republican Senator shares his concerns.

Trump used his Twitter feed Sunday to take aim at Corker, saying that Corker decided not to seek reelection because Trump would not provide his endorsement. A person familiar with the situation immediately disputed Trump’s account to TIME, saying the President had called Corker and asked him to reconsider his decision — and offered his endorsement. Corker later said as much to the Times.

Corker responded to Trump’s Twitter attack by calling the White House an “adult day care center” has further intensified his rhetoric against Trump, expressing concern that his policies could result in a third World War.

Corker and Trump haven’t always been at odds. Corker praised Trump after he gave a foreign policy speech when he was still a presidential candidate, and he began receiving calls from Trump with foreign policy questions. Corker was also said to be a candidate for Vice President, and later Secretary of State. In February, he expressed optimism that the Senate could still work with Trump.

“It’s taking nuggets, massaging them, evolving them to a little bit different place,” Corker told Politico. “I see that as a challenging, but a very positive role for us to play.”