ROBERT COSTA: Crisis management.

President Trump launches airstrikes on Syria in retaliation for poison gas attacks on civilians.

I'm Robert Costa, and we'll examine the significant shift in the president's position on U.S. intervention, tonight on Washington Week.

PRESIDENT DONALD TRUMP: (From video.)

I ordered a targeted military strike on the airfield in Syria from where the chemical attack was launched.

ROBERT COSTA: President Trump says strikes against Syria and President Bashar al-Assad were vital to national security.

PRESIDENT DONALD TRUMP: (From video.)

Assad choked out the lives of helpless men, women and children.

ROBERT COSTA: Russian President Vladimir Putin, an ally of Assad, calls the blitz an act of aggression, while at home the president is finding bipartisan support from many lawmakers and opposition from others who believe he needed congressional authorization.

SENATOR MARCO RUBIO (R-FL): (From video.)

It was the right move.

Assad is willing to use that gas against civilians.

Why would he not be willing to use it against Americans?

SENATOR TIM KAINE (D-VA): (From video.)

President Trump's doing this, finally waking up to the atrocities in Syria, is a good thing, but he should not have done this without coming to Congress.

ROBERT COSTA: Meanwhile, high-stakes diplomacy in Florida, where Mr. Trump is meeting with the president of China to discuss trade and North Korea's nuclear ambitions.

Plus - VICE PRESIDENT MIKE PENCE: (From video.)

Neil M. Gorsuch of Colorado - ROBERT COSTA: The historic confirmation of a Supreme Court justice.

We tackle it all with Nancy Youssef of BuzzFeed, Michael Scherer of TIME Magazine, Karen Tumulty of The Washington Post, David Sanger of The New York Times, and Alexis Simendinger of Real Clear Politics.

ANNOUNCER: Celebrating 50 years, this is Washington Week.

Once again, from Washington, Robert Costa of The Washington Post.

ROBERT COSTA: Good evening.

Barely 100 days into his presidency, Donald Trump declared to Syria and the world that the use of chemical weapons will not be tolerated.

Syria and its closest ally, Russia, blasted the U.S. for its attack on the airbase in Homs where aircraft launched a series of gas attacks on innocent civilians earlier this week.

Many leaders around the world praised the president's actions as proportional and a measured response to Bashar al-Assad's suspected use of sarin.

The airstrikes are a very dramatic departure from Mr. Trump's position in 2013, when Syrian forces launched a similar poison-gas attack on the rebel-held city of Ghouta.

Then, Trump tweeted: "President Obama, do not attack Syria.

There is no upside and tremendous downside.

Save your "powder" for another (and more important) day!"

Pentagon Correspondent Nancy Youssef joins us now with the latest on the Trump administration's strategy in Syria.

Nancy, you've been at the Pentagon day and night since these attacks came about.

What can you tell us about the response in Syria?

Does Assad still have a grip on power, and is he planning any retaliation?

NANCY YOUSSEF: Well, it's interesting.

Assad started the week as a political reality, according to the White House, and by the end of this week there was talk about whether further action needed to be taken against him.

Strategically, I think one of the challenges he'll face is that he's complicated the - Russia's ability to back him militarily.

He arguably has emboldened the opposition, who never thought that the U.S. would intervene in this way - now that it has done so, may feel more emboldened to strike back or have a chance at fighting in this already-gruesome civil war.

And tactically, he's lost about 20 airplanes at that base in Sharyat, which is not a major blow to him but airpower is the one part of his military operation which he dominates over the opposition.

And so seeing that those aircraft are out of service and that the Russians are having to think about things like air defenses changes tactically how he can carry out a war that up until this point he had the belief that he could do anything and not face the wrath of the international community.

ROBERT COSTA: Knowing that part of his forces have been depleted, how does that affect the U.S. response in terms of a second wave of attacks or thinking through what's next in terms of Syria and military action?

NANCY YOUSSEF: Well, the U.S. military has said that there's no intention of conducting further acts.

There was a real effort in these strikes to send a message, deter Assad from doing - using chemical weapons, and at the same time avoiding any further escalation.

That was really the very fine line that the U.S. military was trying to walk with these strikes.

And so the signal we've gotten is unless chemical weapons are used again there's no intention of further strikes on the Syrian force.

ROBERT COSTA: Nancy, do your sources at the Pentagon have any word about whether something besides Tomahawk missiles could be use in the future on Syria from the U.S. perspective?

NANCY YOUSSEF: Well, potentially they could have used, for example, airstrikes using fixed-wing or drone strikes.

One of the concerns in this strike, and I think in future strikes, is that that potentially endangers personnel.

The appeal of using Tomahawks from destroyers is that is minimizes the risk to personnel.

And so there is the potential militarily to do it, but then the risk-reward ratio comes into effect: to what end, and is that worth the risk in a conflict, again, arguably both the U.S. and Russia are eager to not escalate further and turn into a potential proxy war of sorts between the two sides.

ROBERT COSTA: Nancy, stay with us.

David, when we look at this week, what a turnaround from President Trump, from seeming like he wants to be disengaged on the Syrian question and now we have military airstrikes.

What forced the question?

What forced the action?

DAVID SANGER: Well, what forced it was the president of the United States looking at these heart-wrenching photographs and video of children dying, and it tells you how much he reacts emotionally, as we all did, to a scene of horror.

But that scene of horror, as you suggested before, was no worse than what we saw in 2013, when he advocated against our intervening.

So what's different is now he's responsible, now he did not want to be the one who did not enforce the red line - even if it had been set by his predecessor.

I think there was something of an imprecision in language in that scratchy video you heard from Mar-a-Lago because at one point he said we did this attack because it was vital to American national security.

Well, it's not really vital to our security.

Nobody thinks that the Syrians can do this attack in the United States.

It was a humanitarian intervention, something he hadn't given a great deal of thought to when we did interviews with him, and you did as well, last year.

But now I think he needs to go demonstrate, first, that he's willing to use force; and, second, in this case he was given the gift of using force in a cause that no one - Democrats, Republicans, most of the international community - would dispute.

ROBERT COSTA: Karen, you've covered the president for so long.

He has visceral reactions to things.

And David's talking about maybe looking for a strategy and an orthodoxy, but can we expect that from President Trump?

He's not known as a hawk.

He ran as a non-interventionist.

KAREN TUMULTY: He does sort of operate with his gut.

And what's different now - I mean, all of us see these photos and feel horrified and helpless.

The one person who's not helpless, the president of the United States, the commander in chief.

But whether this is some sort of - you know, the overused word with Donald Trump - pivot, is this some sort of new direction for his presidency, or is this just some sort of aberration, we don't know.

And we never know this with Donald Trump because it seems like all of his actions are much more situational than strategic.

ROBERT COSTA: Well, there's this base thing, Michael.

He ran as this non-interventionist who was critical of intervening in Iraq, and now he is working closely with traditional Republican hawks on military strikes in Syria.

MICHAEL SCHERER: It wasn't just when he ran.

Remember, at the inaugural he said to the nation and the world we're not going to worry about people overseas anymore, we're going to put Americans first.

Intervening on a humanitarian basis in Syria is very traditional.

And I think what is remarkable is you have, you know, Democrats and Republicans, the leaders of both the House and the Senate, all coming out and supporting this.

Who would have thought you would hear Nancy Pelosi praising something Donald Trump was going to do a week ago?

And you have members of his base, particularly on the alt-right, outraged at basically him embracing traditional foreign policy positions of the United States.

This is something that President Bill Clinton could have done.

This is something that George W. Bush could have done, something you could have seen - although he pulled back at the last minute - Barack Obama doing, and so Trump is following a very conventional path here.

ROBERT COSTA: Alexis, we're talking about Congress applauding the president for the moment, but eventually a lot of them want to have the president come to Congress and look for authorization.

What's the White House's approach to approaching Congress on this?

ALEXIS SIMENDINGER: Well, the disposition from the administration was, we informed Congress; we are not - we did not ask their permission.

And that is a norm that we have seen since President Obama decided himself that he was not going to succeed and his retreat from actually deploying a missile attack against Assad, and changed his mind and went to Congress and found out what he and David Cameron in the U.K. discovered, which is that it was a very hard lift to try to get that support from the legislative allies that they had hoped to get.

And President Trump made no bones about the idea that he thought it was legal, he thought it was supported - he gave conflicting rationales for that - but that he was not asking for permission.

ROBERT COSTA: I want to go real quick to Nancy on something.

You've been running around the Pentagon reporting.

What do we know about who actually influenced the president's decision here?

Was it National Security Adviser McMaster?

Then I want to get David on this as well.

Was it the - Defense Secretary Mattis?

Was it Secretary of State Tillerson?

Who's driving this change in policy?

NANCY YOUSSEF: Well, on Thursday, when this was being debated literally throughout the day, the sense that we got was that Secretary Mattis and H.R.

McMaster, the national security adviser, were really key in sort of shaping the strike plan and reviewing the option put forth.

This seemed to be coming at a much higher level than past operations, in part because it - the turnaround on it was so quickly.

Usually operations take weeks, if not months, and this was literally something that was decided in less than 48 hours.

And so the approach is something that - of going in and conducting a decisive strike and then leaving is quintessential H.R.

McMaster.

That's the kind of - sort of operation that he prefers.

But in the halls of the Pentagon, one got the sense that this was at such a high level because it was being decided so quickly that it was just a handful of people, namely Secretary Mattis and H.R.

McMaster, both of whom have a decades-long military career.

ROBERT COSTA: Let's bring it back to Secretary of State Tillerson.

David, you're going to be traveling to Moscow next week with the secretary of state.

And you look at his statements on Syria, you see not just - is it about the pictures of the children and what the president's reacting to, but this really is a chess match with Russia as the Trump administration rethinks, perhaps, its policies.

So what does it mean when Tillerson goes to Russia next week and he talks to Putin?

What should we expect there?

And what does this whole episode tell us about the state of U.S.-Russia relations?

DAVID SANGER: Well, the first thing it tells us is that we may well be returning to something that is more our accustomed relationship with Russia, which is to say not terribly good.

The discussion that President Trump had about this as a moment to go rebuild relations; why can't we be friends - you're seeing all that sort of go away.

Interestingly, it's President Trump who's been the least critical - although more critical than he's been in the past - of all of the members of his Cabinet.

Nikki Haley got up today in the United Nations and really let the Russians have it.

You've heard Tillerson do the same.

Now Tillerson himself has got a really interesting dance here.

The last time that he was running into Vladimir Putin, it was to strike oil deals.

He was going as the chief executive of Exxon.

And the question now is, can Mr. Tillerson, somebody who's never shown a particular interest in human rights issues and so forth, stand up and make this the center of the deal, instead of what he was initially planning to go for weeks ago, which was a partnership with Russia to go after ISIS?

ROBERT COSTA: Thanks, Nancy, for joining with us this evening.

We're going to turn right now to another topic on foreign policy/national security, North Korea.

Michael, we were talking earlier today about how it's pretty quiet down at Mar-a-Lago.

The Chinese president's there.

And I thought it was a fascinating moment to have the president launch airstrikes on Syria as he's having dinner with the Chinese president.

What's the takeaway for the Chinese as they deal with this administration, they watch the airstrikes happen?

And what does it mean as they think through the North Korea question?

MICHAEL SCHERER: Yeah, it was interesting.

The White House said today that it was at the end of the dinner that he kind of leaned over to President Xi and said, by the way, while we've been eating, I was launching an attack on Syria.

You know, I think this whole summit in Mar-a-Lago is very - has two different messages.

It's not the Donald Trump of the campaign, who said, I'm going to beat up on China.

This was a very cordial, very welcoming visit.

There wasn't - you know, President Obama, when he met with the Chinese leadership, would sort of try and force some sort of a press event to put the Chinese on the spot.

There wasn't anything like that.

It was all done privately.

There's not much of a readout.

We don't really have any big new policies coming out of it.

It was just an introductory meeting.

I think, for Trump, it's - there's a hope that by approaching with sort of a softer approach than he had said he was going to do, he can get some cooperation on North Korea.

You know, there are very few good options in North Korea, and the best option could be something that involves China, which has an interest in preventing a U.S. attack there or a dissolution of the North Korean regime, putting more economic pressure on North Korea to pressure them to pull back from their nuclear program.

ROBERT COSTA: Do they want to do that?

I mean, it seems like the Chinese are so reluctant to engage with North Korea, because they don't want to have North Korea collapse, right, Karen?

KAREN TUMULTY: But in that sense, though, there may be a message in the Syria attack, in that, you know, China has voted with Russia in the U.N. on Syria resolutions, to block them.

There's a message here to the Chinese as well: that, you know, the United States may take action on its own if - and Donald Trump has flat out said it - if nothing is done.

ROBERT COSTA: It's so different to have military action in North Korea, right, Alexis?

Because you have - and then, Dave, I want you on this as well - because when you attack Syria, you're attacking the Assad regime, but with North Korea, you could have mass migration into China.

You have a possible conflict with South Korea.

ALEXIS SIMENDINGER: Right.

It really caught our attention in the White House - in the press corps to hear the president's national security advisers in the briefing before the Chinese president was visiting talking about how North Korea - the clock had run out.

The time - and we have - we've heard, obviously, the secretary of state say something similar, which is that it's time now to focus on less talk and, you know, more demands on North Korea.

But the White House was trying to say, no, the president wasn't trying to say - send a message, but also, at the same time, coming out tonight was some reporting, I think purposeful reporting, that the administration has some plans prepared for the president, should he decide to pull some things off the shelf about how to attack North Korea, how to sanction North Korea, what to do about Kim Jong-un.

Their attitude is that the president is prepared.

So the message is out there.

ROBERT COSTA: I know, David, I keep coming back to Tillerson with you, but it's a black box reading this administration sometimes on North Korea.

Tillerson's statement after the missile strikes earlier this month was, we've said enough; nothing more needs to be said.

DAVID SANGER: Yeah, that was actually before the missile strikes.

And he hasn't said very much.

The fact of the matter is, they need leverage with the Chinese on North Korea.

If the Chinese were going to solve the North Korean problem, they would have solved it 20 years ago.

Their fear is a collapsed state that ends up with the American forces and the South Koreans up on their border.

And that geography hasn't changed because of a missile strike that we've done in Syria.

What may change is that President Obama - President Trump may go take the steps that President Obama talked about but didn't take, and that is to try a massive increase in both military and economic pressure on North Korea and then open the possibility to negotiation.

And that seems to be their strategy.

How you do that while keeping the North Korean problem from exploding or imploding on you is the trick, because, as Alexis has pointed out, it's - the North Koreans can reach out to you in a way the Syrians never could.

ROBERT COSTA: So Russia remains kind of a chess game for the Trump administration, as does North Korea, for President Trump.

But when you look at Russia here at home, it's kind of a cloud over the administration.

And there's real issues about President Trump's making unfounded allegations against the former national security adviser to President Obama, Susan Rice, and then you had the House Intelligence Committee chairman, Devin Nunes, step down from his role in investigating Russia, though he did remain chairman.

And so we see Nunes recusing himself, at least temporarily, but because he's a target of a House ethics committee investigation about whether he improperly exposed classified information.

Let's remember this all began two weeks ago, when Nunes made a mysterious announcement outside the White House that he had seen evidence that some members of Trump's transition team were visible in incidental surveillance.

Karen, when you look at the Russia issue for the Trump administration, are they moving beyond it with Nunes stepping away, or does it remain a cloud in the sense that the president keeps reviving accusations against the past administration?

KAREN TUMULTY: Well, I think that certainly the people on the Hill needed Nunes to step away from it, because he had completely undermined the integrity of the investigation and in fact had raised questions as to whether Congress is even capable of conducting investigations anymore.

But what the president continues to do and we saw again this week when the - when he sort of conflated Susan Rice's decision as national security adviser to unmask some - ROBERT COSTA: Talking to The New York Times.

KAREN TUMULTY: - to - right - well, to unmask, which is not the same as leaking - that is, she wanted to know the identity of the people that were being contacted.

And - sorry, I'm now conflating it, but Trump conflated all of this as though she were somehow illegally leaking, and he - ROBERT COSTA: He can't give it up, can't give up the issue.

KAREN TUMULTY: - and then he flat out told The New York Times that she had committed an illegal act when there is no evidence that she did.

ROBERT COSTA: And she has denied doing so.

But this is - why - you've interviewed, Michael, Trump about truth and about these issues many times.

Why can't he resist engaging on all this all the time?

MICHAEL SCHERER: He thinks he's winning by doing it.

It's the shiny object strategy.

He's unhappy with the talk about his campaign's ties to the Russians, and so he's created an entirely new storyline that borders on a telenovela - you know, the president wiretapped me.

Maybe - I didn't mean wiretapping.

Maybe it was unmasking that was - that was a scandal.

It looks like a scandal to me.

The whole stagecraft of Nunes coming over to the White House, not telling anybody, going back to the Hill, giving a press conference, coming back to the White House.

I mean, it's a terrific TV show that the president's basically putting on without the help of us own communications staff.

He does it by himself, calling reporters, saying he's upset about it, using Twitter.

And it's created a separate story we have to cover.

DAVID SANGER: It's a separate narrative, but it's one where the details are so confusing.

Everybody's gotten lost in all that.

And the Russian hack and Putin's effort to influence the election, as determined by U.S. intelligence, is a fairly simple storyline.

This whole set of stories about Obama tried to tap my wires and all of the unmasking issues - it's not a simple storyline.

ROBERT COSTA: And it's driven by the president.

We'll see if Representative Conaway of Texas, who's going to take over the Russia part of the probe, will move in a different direction than Nunes.

And of course the Senate Intelligence Committee is conducting its own investigation.

Staying with Capitol Hill, we're coming to a topic I'm glad we're getting to.

(Laughter.)

Finally, the Senate confirmed President Trump's Supreme Court nominee, following a bitter 14-month battle.

Forty-nine-year-old Neil Gorsuch now has a lifetime spot on the high court.

He replaces the late Justice Antonin Scalia, who died in February of last year.

The vote was 54-45, largely along partisan lines.

Republicans exercised, however, the so-called nuclear option and changed the chamber's filibuster rule to ensure Gorsuch's confirmation, a move some Democrats said would end a long history of consensus on Supreme Court nominations.

So Gorsuch is confirmed.

We're getting this at the end of the show.

It's - the Supreme Court's been kind of on the backburner in American politics.

But this does raise questions, Alexis, about the Senate.

By changing the filibuster rule, is it destroying the institution?

ALEXIS SIMENDINGER: Well, one of the fears is that this isn't where it stops; that when you go down the slippery slope and you're seeing a divided nation and you're seeing a divided a Senate, that it's going to beyond - go beyond judges and beyond the Supreme Court, and that it could then begin to erode the idea of a filibuster or minority influence in the Senate, the cooling saucer concept of our two chambers, when it comes to things like, you know, any policy issue or the budget going forward.

So one of things that is worth watching is whether we're now mourning something that we've lost or we're acknowledging something that's true, which is that the world in which we live in is politically divided, the country is divided, and the Supreme Court is also viewed as a partisan or political body.

ROBERT COSTA: And after such a rocky start for the Trump administration, my sources at the White House - and, I'm sure, yours too - they keep hailing this as a win.

It seems to be the lone thing beyond the executive orders, Karen and Michael, that the Trump administration's been able to accomplish.

KAREN TUMULTY: Well, and this was a pick that, had it happened 15 years ago, Neil Gorsuch probably - well, look at Antonin Scalia.

He passed with a unanimous vote, except for two senators being absent.

So Donald Trump made what is probably the most centrist pick that a Republican president could have made.

The next time around, it may not be substituting one conservative for another one.

And also, now that it only takes 51 votes, it may also well be that he may not feel inclined to sort of play for the middle on it.

ROBERT COSTA: Real quick, Michael.

MICHAEL SCHERER: Yeah, Donald Trump likes to win.

And it's interesting to me that the big wins he's had in his presidency are very conventional.

He nominated a conventional conservative.

He got him on the Supreme Court.

He gave a conventional speech to a joint session of Congress.

He was widely praised.

And this military strike on Syria, also very conventional foreign policy - what's interesting, I think, is whether he begins to move away, because he sees he can get more done, can get the points on the board he wants by behaving like past Republican presidents, not like someone trying to disrupt the entire system.

ROBERT COSTA: A conventional win, perhaps, for an unconventional president.

We're going to have to leave it there, my friends.

And thanks, everybody, for watching.

Our conversation will continue online on the Washington Week Extra, where we'll show you who was in the room when President Trump was briefed on the Syria strike.

A look into the president's inner circle of decision-makers.

You want to check it out, and you can find that later tonight at PBS.org/WashingtonWeek.

I'm Robert Costa.

Thanks so much for watching, and enjoy your weekend.