His retaliation came in a Forbes magazine interview published yesterday.
In this October 5, 2017, photo, Secretary of State Rex Tillerson arrives for the first meeting of the National Space Council in Chantilly, Va. President Donald Trump challenged Tillerson to "compare IQ tests", delivering a sharp-edged ribbing that threw a bright spotlight on his seemingly shaky relationship with his top diplomat. "I think it's fake news", Mr Trump said. "And I can tell you who is going to win". The State Department has denied Tillerson ever made the comments.
Tillerson speaks on behalf of the president and the country. Tillerson scores 120, while Trump's is just a crudely done kid's drawing of the president in a truck.
Brown declined to say whether either party has taken an admission test before, but did name several former USA presidents, including Jimmy Carter, Bush Senior and Bill Clinton, whose academic backgrounds and non-political careers "would have propelled them into Mensa".
United States bombers conduct military drills over Korean peninsula
Two supersonic USA bombers have flown over the Korean peninsula in a "show of force" despite Kim Jong-Un's threats to shoot them down.
Trump says he listens to everyone "but ultimately my attitude is the one that matters".
Every meeting between Trump and Tillerson at this point are high-stakes affairs given their extremely fraught relationship.
Trump added in the Forbes interview that Tillerson was "wasting his time" when Tillerson appeared to be reopening talks with North Korea.
Nevertheless, something about the incident still seems to bother Trump, who was due to have lunch with Tillerson at the White House later on Tuesday. "I'm not undermining. I think I'm actually strengthening authority".