WASHINGTON — Washington's chief diplomat Rex Tillerson found himself obliged to defend President Donald Trump's fitness for office Friday after a bombshell new book called into doubt his mental health. In an extraordinary portion of a television interview on foreign policy challenges, Tillerson was asked about claims that Trump has a short attention span, regularly repeats himself and refuses to read briefing notes. I've never questioned his mental fitness. I've had no reason to question his mental fitness, said Tillerson, whose office was last year forced to deny reports that he had referred to Trump as a moron after a national security meeting. And, even in defending Trump, the former ExxonMobil chief executive admitted he has had to learn how to relay information to a president with a very different decision-making