James Comey says Donald Trump isn't mentally unfit for the presidency--but morally unfit.
The former FBI Director said in an ABC interview that Trump insults core democratic values.
It was an unprecedented public challenge to a sitting commander in chief.
"The foundation of this country is in jeopardy when we stop measuring our leaders against that central value of the truth." However, Comey said he'd prefer voters reject Trump instead of him being impeached..