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After a July 20 meeting in a secure room at the Pentagon, Secretary of State Rex Tillerson called President Trump a "moron," shocking the handful of senior administration officials at the meeting, NBC News reports, citing three officials "present or briefed on the incident." The previous day, Trump had threatened to fire the U.S. general commanding the Afghanistan war and compared troop deployment decisions to the renovation of the 21 Club restaurant in New York, but Tillerson was also reportedly upset about being undercut by the president on U.S. policy on Qatar and Iran, among other places.

Then, after Trump gave an overly partisan campaign-style talk to the Boy Scouts, Tillerson — an Eagle Scout and former president of the Boy Scouts of America — threatened to quit, NBC reports, citing "multiple senior administration officials who were aware of the situation at the time." Tillerson, in Texas for his son's wedding, threatened not to return, but was strongly urged to stay on by his closest allies in the administration, Defense Secretary James Mattis and soon-to-be Chief of Staff James Kelly, NBC News says. When he returned, Vice President Mike Pence reportedly arranged a meeting to defuse the tensions and counsel Tillerson to work within Trump's policy framework.

The tensions flared again last weekend when Trump tweeted that Tillerson should stop trying to use diplomacy on North Korea, right after Tillerson had announced direct contact with Pyongyang. The White House declined NBC News' request for comment, and Tillerson's top State Department spokesman, R.C. Hammond, denied that Tillerson called Trump a "moron," was angry over Trump's Boy Scouts speech, or had any policy differences with Trump. You can read more at NBC News.