ROBERT COSTA: Moment of truth, but whose truth?

I'm Robert Costa.

The president and former FBI director accuse each other of lying, and explosive testimony sparks new questions about credibility and political consequences, tonight on Washington Week.

FORMER FBI DIRECTOR JAMES COMEY: (From video.)

I was honestly concerned that he might lie about the nature of our meeting, and so I thought it really important to document it.

ROBERT COSTA: Fired FBI Director James Comey calls President Trump a liar.

In sworn testimony, Comey laid out details of how the president requested his loyalty, then tried to influence the probe into Russian meddling, specifically the ongoing investigation into former National Security Advisor Michael Flynn.

JAMES COMEY: (From video.)

I was fired because of the Russia investigation.

ROBERT COSTA: The president denies it all.

PRESIDENT DONALD TRUMP: (From video.)

No collusion, no obstruction.

He's a leaker.

James Comey confirmed a lot of what I said, and some of the things that he said just weren't true.

ROBERT COSTA: Comey admitted to senators that Mr. Trump's tweet that he better hope that there are no tapes prompted him to take unconventional action.

JAMES COMEY: (From video.)

I asked a friend of mine to share the content of the memo with a reporter because I thought that might prompt the appointment of a special counsel.

ROBERT COSTA: Days later, Robert Mueller was appointed special counsel.

Top Republicans are standing by the president.

HOUSE SPEAKER PAUL RYAN (R-WI): (From video.)

He's new at government, and so therefore I think that he - he's learning as he goes.

ROBERT COSTA: Plus, bombshell revelations about former Attorney General Loretta Lynch and her attempt to redefine the investigation into former Secretary of State Hillary Clinton.

We explore it all with Dan Balz of The Washington Post; Julie Hirschfeld Davis of The New York Times; Pete Williams of NBC News, and Kimberly Atkins of The Boston Herald.

ANNOUNCER: Celebrating 50 years, this is Washington Week.

Once again, live from Washington, moderator Robert Costa.

ROBERT COSTA: Good evening.

A remarkable week in Washington, where scrutiny of President Trump's conduct came to the fore and policy debates, well, they took a backseat.

Today, during a Rose Garden news conference, President Trump responded to the stunning testimony of former FBI Director James Comey, and it was a memorable exchange.

JONATHAN KARL (ABC News): (From video.)

I want to get back to James Comey's testimony.

You suggested he didn't tell the truth in everything he said.

He did say under oath that you told him to let the Flynn - you said you hoped the Flynn investigation you could let - he could let go.

PRESIDENT DONALD TRUMP: (From video.)

I didn't say that.

JONATHAN KARL: (From video.)

So he lied about that?

PRESIDENT DONALD TRUMP: (From video.)

Well, I didn't say that.

I mean, I will tell you I didn't say that.

JONATHAN KARL: (From video.)

And did he ask you to pledge his loyalty - PRESIDENT DONALD TRUMP: (From video.)

And there would be nothing wrong if I did say it, according to everybody that I've read today.

But I did not say that.

JONATHAN KARL: (From video.)

And did he ask for a pledge of loyalty from you?

That's another thing he said.

PRESIDENT DONALD TRUMP: (From video.)

No, he did not.

JONATHAN KARL: (From video.)

So he said those things under oath.

Would you be willing to speak under oath to give your version of those events?

PRESIDENT DONALD TRUMP: (From video.)

One hundred percent.

JONATHAN KARL: (From video.)

And - PRESIDENT DONALD TRUMP: (From video.)

I didn't say, under oath.

I hardly know the man.

I'm not going to say I want you to pledge allegiance.

Who would do that?

Who would ask a man to pledge allegiance under oath?

I mean, think of it.

I hardly know the man.

It doesn't make sense.

No, I didn't say that, and I didn't say the other.

JONATHAN KARL: (From video.)

So, if Robert Mueller wanted to speak with you about that, you would be willing to talk to him?

PRESIDENT DONALD TRUMP: (From video.)

I would be glad to tell him exactly what I just told you, Jon.

ROBERT COSTA: Dan, why did President up the ante this afternoon and offer to speak with Robert Mueller, the special counsel?

DAN BALZ: Well, I mean, he obviously takes very personally what Director Comey did and said on Capitol Hill on Thursday.

It was very, very damning testimony - not definitive, obviously, but it was very damning testimony.

He laid out elements of a case that some people think add up to or point to either obstruction of justice or the abuse of power, the abuse of office.

And Donald Trump is somebody who fights back, and when he feels as though he's been wronged in any even small way - and this is no small way - he lashes back.

And that was part of what he was doing today.

ROBERT COSTA: Julie, does the White House and President Trump's top advisers share his confidence in his strategy?

JULIE HIRSCHFELD DAVIS: Well, I mean, there's no question that they have a strategy.

Their playbook right now is they're going to be defiant, they're going to stick by what the president is saying his version of events is, that they're going to try to undercut Jim Comey's credibility.

And, you know, that's sort of the party line right now for them.

But there's no question that inside the White House among the staff there's a lot of anxiety, and of course you couldn't have listened to that testimony yesterday from Jim Comey and thought that that was a positive thing for him at all.

He stood in the Rose Garden today and said it was very, very good, and he tweeted this morning that he was vindicated.

But there is a real feeling that this is spiraling out of control, and nothing that Donald Trump said in the Rose Garden today is going to lessen that.

It's only - it only seems to get more intense.

ROBERT COSTA: You mentioned the president's version of events.

Kim, when you think about these possible tapes that everyone keeps talking about - the president has mentioned he may have taped his conversations with former Director Comey - do these tapes exist?

The president seems to be unclear.

KIMBERLY ATKINS: Well, he seems to be sort of teasing this out like it's a reality television show, saying, well, the answer will come in the grand finale in a few days or some period of time.

(Laughter.)

You know, the answer - he said that you'll be disappointed in the end, as well, which means that there either are no tapes, or if they are - if there are, he doesn't intend to release them, which could lead to more trouble for him if the - if relevant investigative committees are looking for them and they don't provide it.

ROBERT COSTA: Pete, words matter, especially when it comes to the law, and you cover it so well.

We hear this term "obstruction of justice."

We heard it all week.

What does it mean for President Trump in this situation?

And what are the challenges he faces with regard to that question?

PETE WILLIAMS: So there are lots of aspects to it.

In the most simple version, it's if somebody's going to testify before a trial and you get to them and you offer them some money not to testify, that's obstruction of justice - trying to fix a jury, something like that.

In this context, what it means is anybody who tries to interfere with an investigation or a proceeding, and then the statute uses the word "corruptly" - in other words, for a bad motive.

That's what it means.

So, clearly, here the question is, was the president trying to get the FBI to drop an investigation?

And, if so, would that be obstruction of justice?

You said words matter, and that's why this is so critical, because if the president merely was hinting at or suggesting - or, as he said today, flat out didn't do it - that's one thing.

If Mr. Comey's version is correct, that's another.

And a problem for Bob Mueller is you've got just the two of them in the room.

Yesterday, by the way, the president's counsel came out and said, after Comey's testimony, well, he never said those things.

The only way the counsel would know that is whatever Mr. Trump told him.

ROBERT COSTA: Julie, when you look at the White House's response to this and the president, he's working with Marc Kasowitz, a hard-charging New York lawyer.

And when it comes to this answer about - the question about whether did the president asked Comey to lay off former National Security Advisor Michael Flynn, it's about the word, as Senator Risch said in the - in the hearing, about did he hope to do it or did he want to do it, did he direct Comey to do it.

Are they parsing words over there on Pennsylvania Avenue?

JULIE HIRSCHFELD DAVIS: I mean, I think they are parsing words.

They have to parse words because at this point they're in a legal context.

And that hearing yesterday, there was a lot of back and forth about, well, what does "hope" mean.

And what Comey made very clear was that he took it to mean not, oh, "I wish," you know, or "it would be nice if," but I'm telling you, alone in this room with you - I've cleared the room now of all the rest of my staff, and I'm looking you in the eye and saying, boy, I really hope you drop this, and that he took that as a direct order.

And I guess what's not clear here entirely is whether it matters how Comey took it and how Trump meant it, but that is going to be a matter that Mueller is probably going to have to get to, and we heard the president say he will talk to Mueller about it.

PETE WILLIAMS: And, Robert, two points here.

One is we're talking about potential obstruction on Michael Flynn, but there's a separate question here about whether there was potential obstruction on the whole Russia investigation.

And there's no he said, she said about the fact that the FBI director was fired and that the president said I did it to get rid of this guy who was bugging me about Russia.

ROBERT COSTA: That's such a good point.

We didn't learn much new about the Russia collusion investigation from Director Comey.

PETE WILLIAMS: Only confirmation, as the White House rightly points out, that at the time Comey left office un-voluntarily, Mr. Trump was not under investigation.

ROBERT COSTA: I want to pick up on something Julie said real quick, Pete.

Why did Attorney General Sessions leave the room with Flynn?

And what does that - does that raise any legal questions from your reporting end?

PETE WILLIAMS: You mean at the - at the meeting in the Oval Office when they all walked out?

ROBERT COSTA: Earlier in the year, the president reportedly asked the attorney general to leave the room so the president could have a direct conversation with then-Director Comey.

And it brings up all these questions about Attorney General Sessions and his role in this.

PETE WILLIAMS: So the main question, I think, that's of interest to prosecutors is the fact that it looks like the president was about to do something he didn't want other people to know about, and maybe that's not such a good motive.

And that sort of goes toward the whole obstruction issue.

But I guess Mr.

Sessions really was in a position where he - you know, the president ordered him to leave the room.

What could he do?

ROBERT COSTA: Dan, the Republican Party - it was striking to listen to some of those questions.

They're standing with President Trump.

This is not August of 1974 with the Republican Party, as they did then, walking away from President Nixon.

They seem to be sticking with him.

Is it because they believe in the Republican Party that the president still has a grip on the base, in spite of his low poll numbers?

DAN BALZ: Well, I think that's part of it.

I think part of it is their desire to continue a decent relationship and not let this spiral out of control as they are attempting to put through an agenda that many of them care about as much if not more than the president does.

But I thought one thing that was interesting about that hearing on Thursday was that in almost every case, Republican or Democrat, there was praise for Director Comey as they greeted him, in a sense to say - ROBERT COSTA: You're credible.

DAN BALZ: You're credible.

And I also thought that for the most part the Republican questioning, while not uncritical, was not unduly partisan.

They didn't - they didn't rake him over the coals, if you know what I mean.

And so I took both of those things to mean they recognize the seriousness of this.

They're not ready to make a public break, but in the same way that there are White House staffers who are worried, they're very worried.

ROBERT COSTA: Kim, the Republican senators in that room may have praised Comey, may have said he was a credible person to testify, but President Trump is not making that argument at all.

In fact, he's going after the former director as a leaker.

Is this an effective argument?

KIMBERLY ATKINS: Well, it's you're a leaker.

I think next to being a loser that's probably the worst thing that he thinks he can call them.

And it is effective in that, and to the point of unity with GOP lawmakers.

This is something that GOP lawmakers were very interested in throughout this investigation.

Remember Congressman Trey Gowdy made a big point of that the last time James Comey was before Congress, really digging into this issue of leaking while the Democrats were more focused on the Russian investigation.

And even Marco Rubio, somebody who has never been a close ally of President Trump, made the point that with all this leaking going on, the only thing that didn't leak was the fact that President Trump wasn't under investigation while Comey was there.

So I think it's something that can unite the president and Republicans.

ROBERT COSTA: You're an attorney, Kim.

Is there a perjury question here, as both sides make their accusations?

KIMBERLY ATKINS: Well, I think if the White House pursues perjury, and we know the president is someone who likes to sue.

He was like that as a businessperson as well.

And if he - he already has, essentially, accused James Comey of perjury, saying that he lied.

But if he pursues that, that will be tough.

That might be a self-inflicted injury, because the only way to prove that with two people in the room is that he would have to testify under oath.

And that can cause a lot more problems for him legally than he even has now.

PETE WILLIAMS: Can I say something - I'm sorry - quickly about leaks?

ROBERT COSTA: No, go ahead.

PETE WILLIAMS: The president has always complained about leaks of classified information.

Leaks are illegal, or disfavored, if you're revealing classified information, grand jury material, or something that is supposed to be, for the good of the government, secret.

If it's a leak to report a conversation you once had at dinner or some other setting with the president, every book that's ever been written about the presidency is full of leaks.

ROBERT COSTA: So you're saying, Pete, this argument of executive privilege may be out the window for this administration?

PETE WILLIAMS: Clearly, for several reasons.

One is, they had the chance to assert it before Comey testified, and they didn't.

Now they're talking about what he said.

So - and the president's saying he's willing to talk about it.

There's clearly going to be no assertion of executive privilege.

KIMBERLY ATKINS: And the president has been tweeting about it for months.

So I can't see how there was ever an argument for privilege there.

JULIE HIRSCHFELD DAVIS: And let's not forget that when he fired Jim Comey, the president put out a letter in which he referred to private conversations with Jim Comey, in which Comey, he said, he told him that he wasn't under investigation.

So that was sort of the initial - the original sin of, you know, he can't - it would be difficult for him then now to go back and claim that those were privileged conversations that should never have been referenced.

He referenced them in a public way even before any of this happened.

But I do think that whether or not he pursues a perjury case against Comey, it's clear that his lawyer, Mr. Kasowitz, is laying out the predicate for potentially doing that, because you saw in the statement that he put out yesterday he talked about Comey leaking privileged information, and the point being, obviously, even if it wasn't classified, it was something he should not have been talking about publicly.

PETE WILLIAMS: While they talked about it, which is why it's a crazy argument.

It is and it isn't.

ROBERT COSTA: So it's unlikely executive - most people within the West Wing say that they're not going to probably be able to use executive privilege as a way of blocking future testimony or information.

But, Julie, what is the story with Sessions?

The attorney general offered to resign, it was reported by the Post and The New York Times earlier this week.

Is he going to leave the administration?

JULIE HIRSCHFELD DAVIS: I mean, I would be shocked if he would do so voluntarily.

And it would be extraordinarily difficult now for them to get a new attorney general confirmed in this environment.

But this has just been extraordinary to watch.

I mean, Jeff Sessions was an early supporter, an ardent supporter of Donald Trump.

He campaigned so hard for him.

He was a really close ally.

Trump felt very comfortable with him, he trusted him.

But in the last few months, their relationship really has soured.

And one of the things that really started to precipitate that was his ultimate decision to recuse himself from the Russia investigation, which Trump did not want him to do, did not think he should have had to do.

Now, we know from Jim Comey that there's a lot of information out there that suggests that that was the right call for him, but I think that that just was a real black mark for Trump, and it's not something he'll easily get over.

ROBERT COSTA: Dan, when we read the Comey memo, the statement to the Committee, what struck me was loyalty - the president wanted loyalty, in the words of Comey.

What does that tell us about President Trump?

DAN BALZ: Well, I mean, he sees the world in black and white.

And he sees the world in adversarial terms.

And you're either with him or you're not with him.

And the people who he wants around him are people who are utterly loyal to him, and who will defend him, you know, to the end.

And in Jim Comey, when you have the director of the FBI, you know, that's not anything you should ever say to the director of the FBI if you are president of the United States.

And yet, he did.

But it - but it conveys a mindset of the way he sees the world.

And it's the way he operated in business and he's brought that into the White House.

ROBERT COSTA: But, Kim, if there are no tapes, it's then perhaps the president's word versus former Director Comey's word.

And in that scenario, how does it play out throughout the rest of the country?

Are they really going to value Comey's credibility over the president's?

KIMBERLY ATKINS: Well, I think so far when you check the polls, James Comey has a bit - a bit more credibility over the president at this point in time.

Look, you have a lot of factors.

James Comey said what he said under oath.

He's the former director of the FBI.

And you saw the members of the Senate Intel Committee on both sides of the aisle view that with a lot of credibility and were very respectful to him.

The president has done a lot to undermine his own credibility.

And so that will be tough.

I think with this base, they are with him, they are built - they are baked in, and they're going to defend him any way you can.

But, and also to the point of loyalty, I think the president's loyalty is very transactional.

Like, the president is loyal until he's not.

I mean, he was loyal to Rudy Giuliani.

He was loyal to Newt Gingrich and a lot of other folks who thought would be in the administration.

He's loyal when it's advantageous to him.

And I think that's one issue going on with this Russia probe.

His loyalty to Michael Flynn, even now, is going to be a big point that I think Special Counsel Mueller is going to probe.

DAN BALZ: And on this question of how the public will come down on it, I mean, a lot's going to depend on what Bob Mueller concludes in his investigation.

KIMBERLY ATKINS: Absolutely.

DAN BALZ: I mean, he's going to sort out these questions of does it rise to the level of obstruction or abuse of power?

Who was - who was - who was lying and who wasn't lying between the president and Jim Comey?

I mean, and, you know, Pete, you know better than we do, but we're so far from that conclusion.

I mean, there's just so much.

And instead of getting closer to it, it seems like we keep adding new elements to his investigation.

ROBERT COSTA: Let's remember there was another stunning, unexpected revelation from this week's hearing, and that was former Attorney General Loretta Lynch, in the words of Comey, urged him to refer to the FBI's probe into former Secretary of State Hillary Clinton's email server as a "matter" rather than an "investigation."

It was yet another turn in the Clinton-Comey story.

Many supporters, of course, of Mrs. Clinton's presidential campaign blame her defeat on Comey's announcement about the FBI's efforts in the month before Election Day.

Pete, matter versus investigation, is that a distinction without a difference?

PETE WILLIAMS: No.

It's not, because a criminal - a full-up criminal investigation is a bigger deal.

I mean, in FBI land, investigation is the big thing.

You do an initial inquiry, you look at things.

So investigation means something.

Credit where credit is due, actually The New York Times first reported this, that this was an issue for Mr. Comey several weeks ago.

But what she says in response - what her people say on her behalf in response is that the way Comey described it isn't quite right.

She didn't say he lied, by the way.

But what she said is that they had a meeting before he was going to testify to the House, where he called it an investigation.

Now, we're talking about the Russia investigation here, rather - oh, no, we're talking about the Clinton investigation.

Excuse me.

She said they had a meeting to talk about it, and that they all sort of went around the table and decided what the right word to use was.

And that they all agreed on matter.

And that he at that time didn't pose an objection to it.

What he says is that what bothered him is that the Clinton campaign was calling it a matter, and he thought it sounded like she was aligning her terminology with the Clinton campaign, and that bothered him.

ROBERT COSTA: Yeah.

Julie, Director Comey didn't urge the Justice Department at that time to go with a special counsel because he said he didn't believe there was a case, and that's riled up the conservative right here in the country.

JULIE HIRSCHFELD DAVIS: Absolutely.

I mean, there's - you know, they feel that there was a double standard; that, you know, not only did he make the opposite call in the case of the Russia investigation and Trump that there should be a special counsel, but he actually took affirmative steps to make sure that a special counsel would be named by, you know, committing all of these meetings to - you know, memorializing them in memos, and then providing the memos to reporters so that, you know, the story would come out and everyone would realize there needed to be special counsel, which of course is what happened.

There's no question that this is - you know, this is going to rile up the conservative base, certainly Trump's supporters, and that's useful for them.

So, I mean, there were some takeaways from this hearing, and that's a big one of them, that is helpful to him, at least in terms of activating his supporters and keeping them on his side in what is going to be a pretty painful period for him.

ROBERT COSTA: Dan, how should we evaluate this Clinton revelation in the Comey testimony in terms of the political impact it may have?

DAN BALZ: Well, I think it reinforces people's attitudes about Jim Comey and his handling of that episode.

Now, he - what he said was, if he had pushed for a special counsel in that case, it would have extended that investigation for a year or more, well past the election.

And so, in a sense, he felt they had reached a conclusion; there was no need to, you know, endlessly litigate it.

Now, the people who objected to this at this point are also the people who were happy when Jim Comey did the letter to Congress on October 28th that the Clinton people think helped bring her down.

So, on that investigation, he has detractors on both sides, and it's one of the reasons that the president thought firing him would make people in the Democratic Party happy with him.

ROBERT COSTA: It's been a pretty rough ride for the Justice Department, Kim.

KIMBERLY ATKINS: It has, it has.

I mean, some of the unexpected swipes that we saw landed right on Attorney General Jeff Sessions when this confirmation that something was up that made it likely that he would recuse himself came up, and that is something, I'm sure, that the Justice Department could do without.

In the case of former Attorney General Loretta Lynch, I think one impact also that it will have is the president loves talking about the election, and this gives him yet another soundbite to talk about.

And just today he said this is still an effort by the Democrats to talk - to divert the election.

ROBERT COSTA: What a week.

Thanks, everybody.

(Laughter.)

Our conversation will continue online on the Washington Week Extra, where we'll tell you about President Trump's pick to replace James Comey at the FBI.

You can find that Friday night after 10 p.m. at PBS.org/WashingtonWeek.

I'm Robert Costa.

Thanks for watching, and enjoy your weekend.