Donald Trump's feud with top diplomat Rex Tillerson burst back into the open Tuesday, after the US president joked that he and his Secretary of State should compare IQ scores.
Having loudly dismissed reports that Tillerson had once called him a "moron," Trump refused to let the controversy go, renewing questions about Tillerson's future.
In an interview with Forbes magazine, Trump was asked about last week's report that Tillerson had insulted him behind his back -- a story that both had already denied.
"I think it's fake news," Trump said, before allowing: "But if he did that, I guess we'll have to compare IQ tests. And I can tell you who is going to win."
The interview was published hours before the two men met in the White House for talks on Iran, Turkey and North Korea and then lunch with Defense Secretary Jim Mattis.
Ahead of the sit-down, Trump had insisted he still had confidence in the secretary of state, saying: "I did not undercut anybody. I don't believe in undercutting people."
But White House insiders say that Tillerson's refusal to personally deny an NBC News report that he labelled Trump a "moron" after a July meeting had only deepened the rift.
President 'allowed to joke'
After the meetings, White House spokeswoman Sarah Huckabee Sanders insisted there was no rift between the men -- and that Trump does not think Tillerson stupid.
"The President certainly never implied that the secretary of state was not incredibly intelligent. He made a joke, nothing more than that," Sanders insisted.
"He has full confidence in the secretary of state. They had a great visit earlier today. And they are working hand in hand to move the president's agenda forward."
Over at the State Department, spokeswoman Heather Nauert declared when asked that Tillerson's IQ was "high" but insisted that the top diplomat he had not been offended.
"Speaking with some of our folks who were over there with the president, with the secretary and the president. The meetings were described as positive," Nauert said.
"I think the president is allowed to joke. He's allowed to have a sense of humor … the secretary is more than fine with that," she said of Trump's remarks about IQ.
Since the alleged insult was reported, White House chief of staff John Kelly has been struggling to keep a lid on the crisis, and on renewed rumors of Tillerson's departure.
But that effort that has been consistently thwarted by Trump's tweets and barbed remarks.
Last week, before the report of the insult was published, Trump took to Twitter to accuse the former ExxonMobil CEO of "wasting his time" trying to negotiate with North Korea.
The rebuke revived rumors that Tillerson is unhappy at his post, but he insists he has no intention of resigning.
In Washington, Tillerson, along with Mattis, Kelly and chairman of the joint chiefs Joseph Dunford are increasingly seen as a buffer against Trump's impulses.
Kelly has worked to control the flow of information across Trump's desk and imposed a decision-making structure that was absent in the early days of the administration.
But for many in Washington, even former supporters from the president's own party, he has not yet been successful.
"The White House has become an adult day care center," Senator Bob Corker declared at the weekend, an astonishing public rebuke from a Republican who campaigned for Trump and chairs the Senate foreign relations committee.
Tillerson's departure would be a major blow to those hoping to temper Trump and prevent the slide towards what Corker described as "the path to World War III."
And it could not come at a more sensitive time diplomatically.
Trump is poised to confront Iran by questioning a major nuclear deal later this week and appears set on stepping up his threats against nuclear-armed North Korea.
Tillerson will also play a major role in preparing Trump's monster trip to Asia next month, that will take in Japan, South Korea, China, Vietnam and the Philippines.