He can't even say it in private

GEORGE STEPHANOPOULOS: So connections between the Trump campaign and Russia had been corroborated by the time you left the F.B.I.?

JAMES COMEY: I think all I can say is that-- the-- the work was still underway, the investigation began because of inf-- reliable information that George Papadopoulos was having conversations about obtaining information from the Russians. That's probably as far as I can go at this point.

GEORGE STEPHANOPOULOS: So where did the conversation go?

JAMES COMEY: The president was talking about something that had happened during an airing of a interview he did with Bill O'Reilly on Fox--

GEORGE STEPHANOPOULOS: Oh the Super Bowl interview --

JAMES COMEY: Yeah. The Super Bowl pre-game show where-- and I hadn't asked any questions about this, but the president was just talking about it, he had given an answer to Bill O'Reilly that had been much criticized across the political spectrum when he had said, in response to a question, that he respected Vladimir Putin and said, "That doesn't mean I'm going to get along with him."

And then O'Reilly responded, "But he's a killer." And the president responded, in substance, "But we're killers, too. You think our country's so innocent." I forget the exact words, but that's the gist of it. And that moral equivalence, between the people of our government and Putin's thugs, had generated a lot of controversy.

And so the president was, as I said when I described the dinner, just in a monologue talking about how that was a great answer, what was he supposed to do, it was a hard question, he gave his best answer. And just going on and on and on. Basically we're all agreeing with this if we don't speak.

And having seen it happen during the dinner I thought, "I can't let that happen," 'cause I don't think it was a hard question. I think the second part of his answer is terrible. And so he gave me an opening at some point by saying like, "Yeah, you agree it was a good answer--"

GEORGE STEPHANOPOULOS: So the president wants you to say this was a good answer.

JAMES COMEY: Yeah. In fact, he was telling me it was a good answer and then said-- gave me an opening by saying, "You think it was a great answer. You think it was a good answer." And then he was starting to move on. And I jumped in and I said, "Mr. President, the first part of the answer was fine, not the second part. We're not the kind of killers that Putin is."

And when I said that, the weather changed in the room. And like a shadow crossed his face and his eyes got this strange, kinda hard look. And I thought in that moment, "I've just done something unusual maybe." And then (SNAP) it passed and the meeting was over. And, "Thanks for coming in," and-- and Priebus walked me out. It was like--

GEORGE STEPHANOPOULOS: You had another mob flashback.

JAMES COMEY: Yeah, I did. Although in that moment I was thinking, "I just succeeded," although I hadn't intended to, in ending any personal relationship between me and the president by th-- by interrupting him and also criticizing him to his face. And I went back and told my staff that it happened, and then I thought-- and told them, "That's not a bad thing, because it will help us keep a distance that we need to keep from him."

GEORGE STEPHANOPOULOS: You-- you saw it right there, and we talked about this earlier-- why is President Trump so reluctant to call out Vladimir Putin?

JAMES COMEY: I don't know. I'm struck by it and I'm struck by it both in public and in private. Because I can understand the arguments why the president of the United States might not want to criticize the leader of another country because there's always good reasons to try and build better relationships, I suppose, even when that other leader is someone who is killing his own citizens and engaging in-- in attacks against our country. But you would think that in private-- talking to the F.B.I. director, whose job it is to thwart Russian attacks, you might acknowledge that this enemy of ours is an enemy of ours. But I never saw. And so I don't know the reason. I really don't.

GEORGE STEPHANOPOULOS: Do you think the Russians have something on Donald Trump?

JAMES COMEY: I think it's possible. I don't know. These are more words I never thought I'd utter about a president of the United States, but it's possible.

GEORGE STEPHANOPOULOS: That's stunning. You can't say for certain that the president of the United States is not compromised by the Russians?

JAMES COMEY: It is stunning and I wish I wasn't saying it, but it's just-- it's the truth. I cannot say that. It always struck me and still strikes me as unlikely, and I woulda been able to say with high confidence about any other president I dealt with, but I can't. It's possible.

"At least in my experience, he won't criticize Vladimir Putin even in private," he said. "I can understand why a president...might not want to criticize publicly another leader" in the interests of forging a good relationship. "But privately? Sitting with the person in charge of countering the Russian threat in the United States? Privately not being willing to do that? That always struck me."