ROBERT COSTA: Another firefight in the Republican civil war.

I'm Robert Costa.

GOP senators turn on the president and the president turns to taxes, tonight on Washington Week.

PRESIDENT DONALD TRUMP: (From video.)

We have actually great unity in the Republican Party.

ROBERT COSTA: The president brushes off stinging criticism from two conservative senators, Bob Corker and Jeff Flake.

SENATOR BOB CORKER (R-TN): (From video.)

I don't know why he lowers himself to such a low, low standard and debases our country in the way that he does, but he does.

SENATOR JEFF FLAKE (R-AZ): (From video.)

It is dangerous to a democracy.

Such behavior does not project strength.

It instead projects a corruption of the spirit and weakness.

ROBERT COSTA: As most rank-and-file Republicans steered clear of the rebellion, the president took to Twitter to dismiss his fellow GOP leaders, writing, "they had zero chance of being elected."

And the president's former chief strategist, Steve Bannon, ratcheted up his plan to defeat all anti-Trump Republicans.

STEVE BANNON (Breitbart News): (From video.)

Right now it's a season of war against a GOP establishment.

ROBERT COSTA: As fault lines widen and the stage is set for a rewrite of the U.S. tax code.

HOUSE PRESIDING OFFICER: (From video.)

The nays are 212.

The motion is adopted.

ROBERT COSTA: But can anything get done on Capitol Hill if the Republican Party is fractured?

We'll get answers and analysis from Peter Baker of The New York Times, Nancy Cordes of CBS News, Julie Pace of the Associated Press, and Ed O'Keefe of The Washington Post.

ANNOUNCER: Celebrating 50 years, this is Washington Week.

Once again, live from Washington, moderator Robert Costa.

ROBERT COSTA: Good evening.

This was an extraordinary week in Washington.

Two Republican senators publicly condemned the president, the leader of their party.

It was deliberate, stinging, and revealed a deeply fractured Republican Party.

Arizona's Jeff Flake delivered his scolding in an emotional speech from the Senate floor, calling President Trump's conduct a danger to democracy.

Flake didn't stop there.

He went on to say Mr. Trump was indecent, reckless, undignified.

Hours earlier, Tennessee Senator Bob Corker, who is retiring, sounded the alarm on the president's rhetoric, saying, quote, "The president has great difficulty with the truth."

President Trump was on Capitol Hill Tuesday for a lunch with senators, and he brushed off those verbal assaults in a series of tweets - the sharpest aimed at Corker, who he called incompetent and a lightweight.

Flake and Corker are considered traditional conservatives, not moderates.

They have a relatively strong pro-Trump voting record, and they are also considered, for the most part, part of the GOP establishment.

Peter, all of this Republican chaos, what does it reveal about the party and President Trump?

PETER BAKER: Well, it reveals is - this is what we've known from the beginning, which is this is a hostile takeover.

It's not, you know, a Republican president.

It's a president who has taken over the Republican Party and trying to fit it into his mold.

And in some ways, Jeff Flake made it easier for him this week by leaving the fight.

By saying he's not going to run for reelection, he cleared the way for a more Trumpian candidate who might in fact take that seat in Arizona.

And so the real question at the end of the week is, yes, there's this tumult, yes, there's this great divide, yes, there's this schism, but is it actually working in President Trump's favor in the short term, because it means he will actually put his imprint more on the party?

ROBERT COSTA: We saw, Nancy, Senator Flake speak out, Senator Corker, but they were not for the most part echoed by other Republicans.

Why is that?

NANCY CORDES: It was fascinating.

You know, Flake issued this very passionate call to arms, and basically the party mutinied.

They said no thanks.

You know, he argued that if you don't speak out against the president you're complicit, you're aiding and abetting essentially, and there was mostly silence from Republicans, if not a defense of the president.

You had a parade of them on television the next day saying, you know, he's working really hard to get things done.

And then you had the president himself, of course, pointing out multiple times that he got a standing ovation from Republicans on Capitol Hill.

So it's possible that over time you will see a few more come over to Jeff Flake's side.

But at this point, most of them aren't willing to do so.

ROBERT COSTA: Ed, when you're talking to senators - Republican senators - are you hearing the same kind of grumblings privately from them?

But - you're hearing that?

ED O'KEEFE: A little bit, yeah.

We've heard it most of the year.

And frankly, early on Flake was one of them privately expressing these concerns.

He's now doing it, of course, as publicly as he can.

The problem, and the reason we saw the silence, is, in talking to one Republican strategist yesterday who had reviewed the Arizona polling numbers specifically that have been done by various groups, he said, look, at this point, support for Trump is like what support for TARP was a few years ago, or, you know, where you are on gun control.

It is a bedrock conservative principle.

And if you are crossing the president, if you can't find a way to tolerate him and work with him on something, you're in real trouble.

He said, look at what's happened to Jeff Flake.

And go back, for example, to the Alabama Senate primary over the summer.

Mo Brooks, the congressman who was running, started out well, but as soon as his opponents ran footage of him criticizing Trump as a candidate last year, his numbers plunged.

And they said: Anyone else who attempts this, to go against the president when they're on the ballot next year, is probably going to face the same problem in their state, no matter where it is.

ROBERT COSTA: Julie, you had a headline this week in the AP: "Can the GOP Survive the Trump Presidency?"

Maybe, though, it's a different kind of GOP we're seeing emerging, the traditional conservatives fleeing and a new kind of Republican taking hold.

JULIE PACE: And I think that's exactly it, it's can the traditional Republican Party survive this presidency.

I talk to a lot of Republicans who consider themselves conservatives, who consider themselves out of this traditional, mainstream Republican mold.

And one thing I heard over and over again was this frustration that someone like Jeff Flake, who, yes, probably was going to lose that primary, wasn't staying in and fighting; that if you really care about the direction of this party, if you really believe that the Republican Party's future is where its past has been, not where Donald Trump wants to take it, that you should stay in, you should give voters a choice.

But what we've seen is the opposite, people like Corker and Flake stepping aside.

We've seen a raft of House retirements.

But there is a real fear that if these Republicans who come from this more traditional mold don't at least stay in and give voters the option, then Trump will complete this hostile takeover.

ROBERT COSTA: Navigating all this, you're watching these senators up close.

And, Nancy, you had this fascinating exchange with Senate Majority Leader Mitch McConnell this week about his - the attacks that are happening on the president, and here's what he had to say.

NANCY CORDES: (From video.)

At what point do you have an obligation as a leader of this party to weigh in on these very serious criticisms of the president?

SENATE MAJORITY LEADER MITCH MCCONNELL (R-KY): What I have an obligation to do is to try to achieve the greatest cohesion I can among 52 Republicans, to try to achieve for the American people the agenda that we set out to achieve.

And tax reform is what we are about.

If there's anything that unifies Republicans, it's tax reform.

ROBERT COSTA: It's important to note that that question and answer happened before Senator Flake made his speech.

But he's saying tax reform and the whole Republican agenda is really the thread that's holding this whole party together.

NANCY CORDES: Right, and he went on to say that we now have a president, at long last, who will sign tax reform legislation if we put it on our desk.

And so he couldn't have been any clearer that it is not in his policy interest to go against this president right now, regardless of how he feels and whether he wants to.

He's in it for tax reform.

He's in it for health care, if they ever get there.

You know, he just doesn't see it as a strategic advantage at this point.

And, no, Flake hadn't spoken yet, but Corker had, and George W. Bush had, and John McCain had.

So, you know, it is getting more and more difficult for leaders in this party, who get asked these questions every week, to avoid weighing in when members of their own party are saying that the leader of the party, the ultimate leader, the president, is dangerous to democracy.

How do you ignore that?

ROBERT COSTA: Peter, you wrote a story this week about General Kelly, the White House chief of staff.

And picking up on all of these points, you see inside the White House there doesn't seem to be a lot of alarm about these breaks in the ranks.

In fact, General Kelly seems to share a lot of the president's view on the party and what needs to happen.

PETER BAKER: Well, I think he does.

I think one of the things we've learned about General Kelly in the last week or so is that he's actually much more aligned with the president than people had assumed.

I think there was this idea that he was the straight-shooting general who wasn't particularly ideological, who might come in and impose order on a pretty disordered White House.

And some of that is obviously the case; he has put in a much more disciplined operation, certainly down.

I don't know about up.

But in fact, he obviously - you know, we saw that he actually shares a lot of the president's both ideological point of view, particularly on immigration and on issues like traditional values, and he shares the president's willingness to mix it up.

He got out there and attacked the Democratic congresswoman who was attacking the president, something most chiefs of staff probably wouldn't do themselves.

But you're right; I mean, there's not, I think, a lot of panic in the White House about Bob Corker or Jeff Flake.

I think, for one thing, the president likes to mix it up with people, and these are two people he doesn't mind mixing it up with.

And from his point of view, he scared them out.

That's the way he's going to look at this: I scared them out because they weren't for me, they couldn't get elected dogcatcher.

That's what he said about Bob Corker.

So his narrative, rightly or wrongly, is this is a good thing because it's going to make the Republican Party stronger.

ROBERT COSTA: Ed, what do you make of Senator Paul from Kentucky and - you know, Senator Paul and Senator Graham from South Carolina?

They're playing golf with President Trump as all this drama is happening among some of their colleagues - they're building a relationship with President Trump.

So where's the disconnect here between these two senators?

ED O'KEEFE: I think those two specifically are trying.

They're trying perhaps for their own interest and on behalf of their colleagues to spend some time with the president, to get to know him better, to try to explain things to him, and to hear him out.

And undoubtedly, they're coming back and they're sharing those observations with their colleagues.

They're also two of the best golfers, at least in the Republican Conference.

(Laughter.)

That's why they're out there.

And the president's a good golfer, but Rand Paul especially is quite a good one.

So, I mean, when the president calls to play golf, what are you supposed to say, right?

ROBERT COSTA: And the thing about this whole week is it wasn't just about Senator Flake versus President Trump, Senator Corker versus President Trump.

There's another whole battlefield in this Republican civil war.

President Trump's former White House Chief Strategist Steve Bannon called these two retirements that happened a monumental victory for the Trump movement.

Bannon's out there, and he's declared war on his own party, vowing to push out all problematic Republicans in next year's midterm elections.

He's also called himself the president's wingman.

But the question is, Julie, is he really acting on the behalf of the president, or is he trying to build a movement that's almost separate from President Trump?

JULIE PACE: Well, it's a really fascinating question.

I think that Bannon sees himself as pushing the true interests and hopes and dreams of the president, even if, on paper, he'll end up with races heading into next year where they're actually supporting different candidates.

He really is actually pitching himself that way.

And I've talked to some folks who are working on some of the races that we expect to have Republican, you know, inter-party fights - Mississippi, for example - and it's fascinating.

They say that voters look to Bannon and actually see him as someone who is expressing the Trump interest, even if Trump has picked the other candidate.

And we saw that in Alabama.

A lot of voters that I talked to in Alabama said that they believed that Trump was really with Roy Moore, even though he went down there and held a rally for Luther Strange.

That is just so incredible that voters have kind of drawn this distinction between who Trump actually may be backing on paper and who he really wants in the Senate.

It's just - I've never seen anything like it.

ROBERT COSTA: Can Leader McConnell push back?

NANCY CORDES: He's trying, but it's a very delicate dance, because he's trying to avoid criticizing the president.

And yet he is, you know, going - has signaled that he is going to push back against his former chief strategist.

And he said last week - you know, he's dealt with this before.

It's just that, you know, in the past it was the tea party backing these candidates instead of Steve Bannon backing these candidates.

And he - ROBERT COSTA: What's the difference between those two things, the Bannon movement and the tea party movement?

Is there - NANCY CORDES: Well, there are a lot of similarities.

But, you know, in general it's candidates to the right of, you know, some very conservative Republicans as it is who are already in the Senate.

And what's different this time around is that it's candidates who are willing to pledge total allegiance to President Trump.

You know, we talked to Charlie Dent, who is a Republican from Pennsylvania, a moderate, this week, who is retiring, and he said the litmus test in his party has changed.

It's no longer purity versus pragmatism.

He said the new litmus test is a loyalty test, are you loyal to President Trump.

Are you loyal to one person?

And he said that is a trend in his party that makes him uncomfortable, and it's part of the reason he's retiring.

ED O'KEEFE: And then Senator Flake was making a similar argument this week.

I think one thing, you're going to see Bannon engage in Mississippi, probably in Nebraska or Wyoming, maybe Utah.

He's already conferring there.

He has weighed in on the Arizona race.

But I would not allow - well, we shouldn't think that Flake's decision to go was fueled by Bannon.

That specific race is quite separate from what Bannon is now trying to do everywhere else, because Flake was having problems even a year ago.

Republicans out there remember that he voted for President Obama's Supreme Court justices, that he worked on immigration reform with Democrats, that he's for global trade deals, that he was for opening up diplomatic relations with Cuba.

It's a very different case from all these other ones that are going to be more loyalty and ideological purity tests.

PETER BAKER: And I think for the president, I think the strategic ambiguity of whether it's him or Bannon is actually a good thing.

Whether he intends it to be or not, I don't know.

But the idea that we don't really know whether he's for him or not allows him to have a card to play.

He's got the sword of Damocles hanging over these incumbents.

Now, he called several of them after his meeting with Senator McConnell last week and said: I'm for you.

Don't worry.

I'm going to be with you.

I don't know if any senator would actually necessarily trust that, because from day to day his feelings tend to switch.

But it's not a bad thing for him, as he sees it, to have Bannon out there as his cudgel, whipping the party into shape.

And then he can be the good cop, saying I'm for you, don't worry, now that you voted for me on tax cuts.

It's awkward, though, because you do need every single one of these votes for these upcoming decisions.

JULIE PACE: Well, remember, when he went down to campaign for Luther Strange, he got onstage at the rally and said, maybe I made a mistake and I'll campaign for Roy Moore if he wins.

That's quite a risk to take if you're someone like Roger Wicker and you invite him down to campaign for you in Mississippi.

PETER BAKER: Right, exactly.

ROBERT COSTA: Ed, amid all this - I want to get your take on this, too, Nancy - where are the Democrats?

I spoke to Senator Bob Casey of Pennsylvania this week, and he said amid all of this on the Republican side, he's still wary about working with President Trump on taxes.

Democrats are worried they're not going to necessarily see gains from this Republican civil war, and they're not really ready to work with President Trump.

ED O'KEEFE: They're definitely not on taxes.

They're definitely not on - they're holding firm on health care.

And immigration and the issues over DACA will certainly be a fight to come.

Remarkable unity, because they just don't see any incentive, both from a policy and a political perspective.

But you talk to party leaders - I was in Las Vegas last week talking to state party chairs.

They are very concerned that the base will rest on its laurels, will fall back on the, yeah, but we're not Trump, or we're not that crazy Republican that's running, and that they have to focus on a positive why you need to vote for us message, as opposed to just don't vote for them.

They're struggling with that still, but I think they're beginning to realize more and more, the more you focus on bread-and-butter issues while the Republicans are fighting amongst themselves, the better chance they'll have.

NANCY CORDES: Right, but you got to break through, and that's the challenge.

When, you know, you've got this very raucous civil war going on, how do you break through that and get your message out there?

Yes, they love the fact that Steve Bannon is fighting with Mitch McConnell.

They think that they have a shot now, even in a red state like Arizona, to pick up a seat because Kelli Ward, they think, you know, who is right now the leading Republican, is beatable.

And even Mitch McConnell kind of went through a list last week of all these tea party candidates in 2010 who should have - you know, who were in seats that they could have won - folks like Christine O'Donnell, "I am not a witch," in Delaware; or Sharron Angle in Nevada.

And he said, you know what all these people have in common?

I'll tell you, they're all in private life and a Democrat is in the Senate.

And he said, that's what's going to happen to us if some of these fringe candidates, you know, end up picking off our incumbents.

ROBERT COSTA: So, as we're watching all of this, all this acrimony inside the Republican Party, we have to pay attention to the policy that they hope is going to unite this party and keep it together.

And House Republicans did come together at the end of this week to pass their budget for next year, which, long story short, clears the way for tax reform procedurally.

But this debate over how to rewrite the tax code and not increase the deficit is certainly creating divisions among Republicans.

Lawmakers from high-tax states like New York and New Jersey are opposed to eliminating the federal tax deductions for state and local taxes, and there is also growing bipartisan opposition to a plan to cap pretax contributions to 401(k) retirement accounts.

The specifics of this plan, the GOP plan, are being closely guarded until next week.

But we do know lawmakers would have to find over a trillion (dollars) in savings to offset the revenue-losing effects of these tax cuts.

Cutting taxes, let's remember, has always been a unifying issue for Republicans, but it has not been this year, has it, Ed?

ED O'KEEFE: No.

This vote in the House was really telling, and is a warning sign for what may come here in the next few weeks.

The goal in the House is to get tax reform done by Thanksgiving.

Even if it does, you've got to keep an eye on the whip count.

Barely a majority of those present voted for it because you had 20 Republicans, including several from Upstate New York and New Jersey, vote against it.

Look, I'm from Albany.

I remember property taxes are too high, the state tax is too high.

If you're a Republican incumbent voting for a budget that would in essence raise taxes on your constituents, you should start looking for a new line of work because it's intolerable, and that's why they voted against it.

If that doesn't change, they're unlikely - in the agreement, if there isn't some change in that decision to exempt that, they probably won't vote for it again, because they know this - ROBERT COSTA: So this is very fragile plan right now?

ED O'KEEFE: Absolutely it is.

ROBERT COSTA: Very fragile.

ED O'KEEFE: And it won't be as big an issue in the Senate, but it definitely is in the House.

JULIE PACE: That issue of the state and local taxes is a huge one.

I mean, you're talking - when you look at some of these estimates, you're talking an average couple's income tax could go - or taxes could go up $9,000, $12,000.

How do you go back as a sitting House member and say I voted for a tax plan that caused you to pay that much more money?

Puts them in an impossible situation, and it completely wipes away what Republicans see as the political benefit of actually passing taxes, which is to give them at least one thing to head home with next year that's tangible that they did.

PETER BAKER: And assuming they get rid of that, that's the only thing that they have to argue that this is really tax reform as opposed to tax cuts.

They're not really redoing the tax code the way Reagan and the Democrats did in 1986; what they're doing is cutting taxes.

That may be a perfectly fine goal, but it's not rewriting the code to make it fairer or to make it more balanced, to cut - to, you know, cut off loopholes or to cut off unnecessary tax benefits, raise some of the money that will be expended by the tax cuts that they do plan.

And in fact, you know, you see more and more they're dumping the tax reform language for the tax cut.

ROBERT COSTA: President Trump is telling people in private I'm told just call it a tax cut, people don't want to deal with Speaker Ryan's tax reform.

He just wants a tax cut.

But, Nancy, one of the things - President Trump's fingerprints are all over this process, some Republicans argue, for better and for worse.

On the 401(k)s, Republicans were thinking about lowering the threshold.

Now the White House is negotiating with the Republicans to raise the cap for contributions to 401(k)s. It tells us, maybe, that President Trump is involved, but he also could rock the boat.

NANCY CORDES: He's involved, but he could say he's for something one day and get blowback, and the next day say he was never for it, and so Republicans know that that's what they are dealing with.

And the problem is that he himself has nixed some big ideas that they've had for ways to raise revenue.

It wasn't just that.

Before that it was the border-adjustment tax.

Remember, this was Speaker Ryan's big idea to tax imports, and the president said no to that as well.

And to your point, Peter, if they can't come up with any ways to raise revenue, whether it's the 401(k)s or the state and local taxes, what they're going to have to do is settle for a smaller package of tax cuts because you have fiscal conservatives like Bob Corker who are going to say I'm not going to vote for $5 trillion worth of tax cuts.

Yes, I might support a smaller package of tax cuts, but you're going to have to really radically scale back your ambition.

ROBERT COSTA: So if they can't get the deficit hawks, like Senator Corker, what about the Democrats, Ed?

Senator Donnelly, he's up in a state President Trump won.

No?

You're shaking your head.

(Laughter.)

ED O'KEEFE: No, they're not.

ROBERT COSTA: Why not?

ED O'KEEFE: They would have by now.

Look, we did something on this last week.

We've checked with all the moderate Democrats who have been wooed, whether it was Joe Manchin in West Virginia, Heidi Heitkamp in North Dakota, Joe Donnelly in Indiana.

All of them say if you're going to bust the deficit the way you're planning on doing it this way, if you're not legitimately lowering middle-class taxes, don't count me in.

And there have been attempts by the vice president, the president, the majority leader; so far, nothing.

And look, I've been told by Democratic aides our bosses would love to find a way to work on this, if anything because it would make life as a senator more interesting, but there's absolutely no room for them to do it right now.

JULIE PACE: No, I think that's really true.

I mean, you saw the White House go after a Heidi Heitkamp.

They really thought they could get a Joe Donnelly to get onboard.

Democrats don't see any political incentive.

And I think this does speak to the White House's ability to get people on both sides onboard.

Trump has not proven to be particularly good at getting Democrats to work with him, even though he has relationships with some of them.

And in terms of working with Republicans, to Nancy's point, he's so inconsistent in his messaging.

And one thing that I think is really important to know about the behind-the-scenes negotiations here is Trump's advisors are not particularly effective when they go up to Capitol Hill, people like Gary Cohn, like Steve Mnuchin - ROBERT COSTA: Treasury secretary.

JULIE PACE: The treasury secretary.

Lawmakers don't feel like these people are negotiating partners for them.

They come in with pretty heavy-handed messages, and you see Republicans just kind of say, OK, we're going to humor you for a little while, but they don't see them as negotiating partners.

ROBERT COSTA: Peter, you're a student of history.

I love that you are.

How important is this tax plan for President Trump?

PETER BAKER: Well, I think it is important because - for all the reasons we've said.

It is a unifying thing after a year of very, very big fractiousness within his coalition, within his party.

It's hard to imagine going into an election year next year without something to call a victory.

And yes, it's true it took President Obama a long time to get his health care bill through, he had to go into his second year, but by that point he already had a pretty big stimulus package, he had a lot of other things he had done.

President Trump's going to end this year, if this doesn't happen, without anything major legislatively to cite.

He's going to talk about Neil Gorsuch.

That's not really legislation.

That's confirmation, that's fine, but it's obviously not changing the system, and that's what he came here to do.

He came to change the system.

ED O'KEEFE: And that is why, to that point, you will see the Senate spend most of the next few weeks just confirming judges, because they know that that is one way to bolster the president's legacy and Republican legacy as well, especially going into next year.

ROBERT COSTA: But judges may not be enough, even for Leader McConnell.

NANCY CORDES: Right, and you know, there's only so long that they can talk about Neil Gorsuch, you know?

In 2018 you can't be saying from the White House podium, well, we got Neil Gorsuch.

You know, you have to do - PETER BAKER: Every president gets Supreme Court justices through, you know?

It just kind of - (laughter) - ROBERT COSTA: We're going to have to - we're going to have to leave it there, my friends.

What a week, again, in Washington.

Thanks, everybody, for being here - Nancy, Ed, Peter, Julie.

It was a great conversation.

If you want to hear more from this panel, check out our Washington Week Extra, where we'll talk about the release of the JFK files and how women on Capitol Hill are showing their solidarity with victims of sexual harassment.

You can find that later tonight and all weekend long at PBS.org/WashingtonWeek.

I'm Robert Costa.

Have a great weekend.