James Clapper, the former Director of National Intelligence who has been repeatedly cited by Trump (most recently in a Fox News interview) as having said there's no evidence of collusion with Russia, told George Stephanopoulos on ABC's This Week that if the FBI had such evidence, he would not have known.
"There could have been, might be, I don't know," he said.
Clapper also appeared on CNN's State of the Union. The key exchange:
Clapper: "... I think as well our institutions are under assault internally."
Jake Tapper: "Internally from the president?"
Clapper: "Exactly.... The founding fathers in their genius created a system of three coequal branches of government and a built in a system of checks and balances and I feel as though that's under assault and is eroding."