Americans from both sides of the political spectrum should be alarmed by Trump's words and behavior. The nation must confront the fact that beyond his hateful character, he is crippled cognitively and showing clear signs of mental illness.

There's no need to resort to armchair psychology to interpret what's apparent. If victorious, Trump would be the oldest president ever inaugurated. In recent weeks, he has canceled an increasing number of public appearances, with Trump's own campaign citing the candidate's exhaustion. When he does appear publicly, Trump struggles to complete sentences or sustain coherent thoughts, and has shown a pronounced difficulty concentrating and a tendency to repeat himself, sometimes within the same sentence.