In recent weeks, a narrative has gained traction in Washington questioning whether Donald Trump is capable of being the president. Michael Wolff's gossip-filled book portrayed Trump as a "child," a "dope" and an "idiot" incapable of processing basic information or having a substantive conversation with his advisers. Despite Wolff's credibility issues, the story line has had an impact: A Post-ABC News poll found that 47 percent of Americans now question Trump's mental fitness.