Donald Trump’s fractious relationship with the Republican establishment reached a bizarre new level on Sunday when Senator Bob Corker described the White House as an “adult day care center” and warned that the president risked setting the US “on the path to World War III”.



An extraordinary exchange between Trump and the chair of the Senate foreign relations committee began when Trump accused Corker, who is retiring, of “not having the guts” to run for re-election.

In response, Corker tweeted: “It’s a shame the White House has become an adult day care center. Someone obviously missed their shift this morning.”

Trump also said that Corker had “begged” him for an endorsement for re-election. “He also wanted to be secretary of state, I said ‘NO THANKS’,” Trump tweeted. “He is also largely responsible for the horrendous Iran deal!”

In a statement to the Guardian, Corker’s chief of staff, Todd Womack, directly contradicted Trump. “The president called Sen Corker on Monday afternoon and asked him to reconsider his decision not to seek re-election and reaffirmed that he would have endorsed him, as he has said many times,” he said.

Corker was considered for both vice-president and secretary of state and was a key Trump ally during much of the 2016 campaign. He has since become a vocal critic.

In an interview with the New York Times later in the day, Corker said he was alarmed about a president who acted “like he’s doing The Apprentice or something” – a reference to the reality television show Trump had once hosted.

“He concerns me. He would have to concern anyone who cares about our nation,” the senator said, adding that Trump’s threats towards other countries could set the nation “on the path to World War III”.

Corker is an important and supportive voice on the deal between Iran and six major nations including the US that restricts Tehran’s pursuit of nuclear weapons. It was reported this week that Trump, against the wishes of senior advisers, will not re-certify the deal. That would put it in the hands of Congress, which would decide whether to reimpose sanctions, a move that would threaten the deal’s existence.

Corker announced his decision to retire last month. “The most important public service I have to offer our country could well occur over the next 15 months,” he said, hinting at his opposition to the president. “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.”

The president called Senator Corker on Monday … and reaffirmed that he would have endorsed him

Last week, he made headlines when he implied that Trump was leading the US to the brink of “chaos”.

Speaking to reporters on Capitol Hill about reports that the US secretary of state, Rex Tillerson, called Trump a “fucking moron” and considered resigning, Corker said: “I think Secretary Tillerson, Secretary [of defense Jim] Mattis and Chief of Staff [John] Kelly are those people that help separate our country from chaos.”

Asked if he was referring to Trump, he said: “[Mattis, Kelly and Tillerson] work very well together to make sure the policies we put forth around the world are sound and coherent. 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.”

Rex Tillerson pledges loyalty to Trump: 'I have never considered leaving this post' – video

On Wednesday, Tillerson denied he had thought of resigning but did not say he had not called the president a moron, leading to reports of presidential fury. Speaking briefly to reporters on Saturday, Trump said he and Tillerson had “a very good relationship” but said the secretary of state could be “tougher”.

Last weekend, the president, who in his debut at the United Nations said the US could “totally destroy” North Korea, slapped down his top diplomat over efforts to pursue talks. On Saturday, Trump tweeted that “only one thing will work” to rein in Pyongyang. In his remarks to the press, he refused to clarify what that meant.

Corker has also said he could oppose moves by Trump and congressional Republicans to pass tax reform, a priority after the repeated failure of attempts to repeal and replace the Affordable Care Act. Corker has insisted that any changes to the tax code must reduce the deficit. Trump’s plan would probably increase it. Republicans hold a slim 52-48 majority in the Senate, making defections costly.

Later on Sunday, Trump tweeted again: “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!”

Trump’s endorsement for Senate races, meanwhile, may be of dubious utility. Last month in Alabama, Luther Strange, the man Trump endorsed for the seat vacated by the attorney general, Jeff Sessions, lost a party primary runoff to Roy Moore, a hardline conservative twice removed from the state supreme court.

