Secretary of State Rex Tillerson called President Donald Trump a “moron” this summer, according to a new NBC News report detailing tensions between the president and his chief diplomat.

Tillerson said that about Trump on July 20, after a meeting at the Pentagon with top national security officials and Cabinet members — just four days before Trump gave an inappropriately political speech to the Boy Scouts of America. According to the report, that speech led Tillerson to consider resigning from the administration.

Though tensions between the two are clearly running high, it’s interesting to note what didn’t anger Tillerson this much, as far as we know. It wasn’t Trump’s response to Charlottesville; it wasn’t the president sending around 3,000 more troops to Afghanistan without a clear strategy; it wasn’t Trump undercutting his diplomatic initiatives with Qatar and North Korea; and it wasn’t even Trump’s son-in-law and top adviser Jared Kushner taking an expansive foreign policy portfolio — including Middle East peace and China — away from the State Department. Instead, it was the president’s speech to young kids.

But Tillerson kept his post in part because Vice President Mike Pence intervened. Pence gave Tillerson a “pep talk” on better ways to deal with Trump, and other top officials — like Secretary of Defense Jim Mattis and now Chief of Staff John Kelly — requested that he stay on, according to NBC News.

A State Department spokesman denies that Tillerson thought about quitting or called Trump a moron.

Tillerson has reason to be angry at Trump

As the nation’s top diplomat, Tillerson speaks on behalf of the president and the country. But on multiple occasions, Trump and Tillerson haven’t been on the same page.

In June, Tillerson defended US ally Qatar during its diplomatic spat with Saudi Arabia and other Middle Eastern countries. Just one hour later, Trump undercut Tillerson and slammed Qatar. “I've decided, along with Secretary of State Rex Tillerson, our great generals, and military people, the time has come to call on Qatar to end its [terrorism] funding,” Trump said at a press conference alongside the president of Romania.

On September 20, Tillerson told reporters that Trump was “still considering” whether the US would remain in the Iran nuclear deal. But just a few hours earlier, Trump told reporters he had made up his mind — though apparently he didn’t tell his secretary of state.

And after Tillerson traveled to China in late September to start a dialogue with North Korea, Trump publicly undercut his effort. “I told Rex Tillerson, our wonderful Secretary of State, that he is wasting his time trying to negotiate with Little Rocket Man,” Trump tweeted on October 1, using his insult for Kim Jong Un. “Save your energy Rex,” he added in a following tweet, “we'll do what has to be done!”

So if there’s anyone in the Trump administration who might have a grudge against the president, it’s Tillerson.