“I’m going to ask the FBI director, ‘was there a counterintelligence investigation opened up regarding the president as being a potential agent of the Russians?’” Graham said. “I find it astonishing, and to me, it tells me a lot about the people running the FBI, McCabe and that crowd.”

Graham then promised to use congressional oversight as a check on the FBI, not on Trump.

“If this really did happen, Congress needs to know about it,” Graham said, “and what I want to do is make sure, how could the FBI do that? What kind of checks and balances are there?”