GWEN IFILL: Upheaval everywhere as a trade deal muscles its way through Congress, a train accident revives the infrastructure debate, Arab leaders come to Camp David, and Jeb Bush comes to grips with the legacy of Iraq, tonight on Washington Week.

SENATOR SHERROD BROWN (D-OH): (From video.)

As we compete in the world economy, Americans should not be patsies for other countries' cheating.

SENATOR ORRIN HATCH (R-UT): (From video.)

We've got to be in the real world where we can trade with all these other countries and receive all the benefits of those free-trade agreements.

The president happens to be right on this.

GWEN IFILL: Labor unions, corporations, Republicans and Democrats square off as the president attempts to nail down a legacy-enhancing trade deal.

A tragic train derailment revives another Washington debate.

JOAN HELFMAN (Amtrak passenger): (From video.)

We were just on the train and all of a sudden it started to shake.

GWEN IFILL: Could spending more on the nation's infrastructure save lives?

HOUSE MINORITY LEADER NANCY PELOSI (D-CA): (From video.)

The Republicans have been very much against Amtrak for a very long time.

HOUSE SPEAKER JOHN BOEHNER (R-OH): (From video.)

Are you really going to ask such a stupid question?

GWEN IFILL: At Camp David, Arab leaders ask the president, is the U.S. committed to their security?

PRESIDENT BARACK OBAMA: (From video.)

Let me underscore, the United States keeps our commitments.

GWEN IFILL: But the prospect of a nuclear agreement with Iran casts a shadow.

On the 2016 campaign trail, Jeb Bush stumbles over the question would he have gone to war in Iraq.

Covering the week, Manu Raju, senior congressional correspondent for Politico; Fawn Johnson, correspondent for National Journal; Peter Baker, chief White House correspondent for The New York Times; and Ed O'Keefe, political reporter for The Washington Post.

ANNOUNCER: Award-winning reporting and analysis.

Covering history as it happens.

Live from our nation's capital, this is Washington Week with Gwen Ifill.

Once again, live from Washington, moderator Gwen Ifill.

GWEN IFILL: Good evening.

Normally debates about trade are kind of dry - easy to ignore, hard to understand.

The last time one caught fire it took Al Gore debating Ross Perot on CNN - remember that?

- to capture the nation's attention.

That was in 1993.

This time the fight over the prospect of a Trans-Pacific Partnership has ignited debate that has Democrats warring among themselves.

Among those leading the charge against the White House, Oregon Senator Ron Wyden.

SENATOR RON WYDEN (D-OR): (From video.)

You can pack trade agreements full of lofty goals and principles.

You can amass all of the enforcement ideas you might want.

But it doesn't do any good, Mr. President, if you don't have real enforcement tools and you make sure that they aren't locked in a shed.

GWEN IFILL: But Republicans mostly took the president's side, arguing that the deal is essential for economic security.

So how did we get to this strange bedfellows moment, Manu?

MANU RAJU: It really started in November, after the Republicans took back control of the Senate.

I mean, remember, the president has wanted this trade agreement, the Trans-Pacific Partnership, and the fast-track authority that goes along with it for some time.

But it was Democrats, when they controlled the Senate, that rejected that.

Harry Reid, when he was majority leader, said he wasn't going to put it on the floor.

So Republicans came in here knowing that this was probably going to be one real significant piece of bipartisan legislation they could get through because of the fact that the Republicans, by and large, support free-trade deals, they support this Trans-Pacific Partnership, and a fraction of the Democratic Party supports pro-trade deals.

And the president is in that camp.

The challenge for him, though, is that an overwhelming majority in Congress from his party strongly opposes it.

GWEN IFILL: Did the Republicans - you know, I don't want to say that they may have seen this coming, but did they recognize the potential for a split in the Democratic Party that would make it look like they were getting things done and the Democrats were not?

MANU RAJU: Yeah, I think they certainly did.

And what's been interesting to see is this Mitch McConnell-Barack Obama moment in this as well.

I had a chance to talk to him a couple weeks ago, and he was praising Obama lavishly over this for taking on his own party.

And that's the one thing that the Republicans have asked the president to do on this, to go after people like Elizabeth Warren in order to give cover to the folks who are willing to break ranks and taken on particularly the labor unions that are coming after this pretty hard.

PETER BAKER: Manu, he has in fact gone after Elizabeth Warren, very specifically by name said she's absolutely wrong.

And the worst thing a politician can say about another politician, he said she was just a politician.

(Laughter.)

But what is her actual role in this?

Is she a chairman of a committee?

Does she have a specific role on this particular thing?

Why is she so front and center?

MANU RAJU: She really just represents that ideological point of view on the left.

She's really not the big player on the Hill on this.

Ron Wyden, who you just showed, Gwen, is clearly the big player on the Democratic side.

He's the ranking Democrat on the Finance Committee and he's in a challenging position trying to get this bill through.

He actually supports that bill, but he also has tried to placate those folks like Elizabeth Warren on the left who are trying to fight this pretty hard.

People like Sherrod Brown also, the Ohio Democratic senator, liberal populist, is aggressively fighting this as well.

She really represents - she has that ability to galvanize folks on the left.

She's more of a message person on this issue and on many issues on the Hill, and she's using that pretty effectively to generate some of that opposition from the outside.

FAWN JOHNSON: And Manu, I mean, I've been covering this and I've talked to Democrats who are just passionately opposed to not only the Trans-Pacific Partnership, but TPA in general, and then I've talked to Republicans who are passionately for it.

And so do we know if this is a good deal for the country or not?

MANU RAJU: It's hard to say.

You know, it really just depends on who you ask, I mean, given that the dividing lines are so pretty stark in this.

And this is such a sweeping agreement.

I mean, this is a 12-nation agreement.

It affects 40 percent of the world's economy.

It's going to affect virtually so much of commerce across the globe.

In addition to that, we really don't know a lot of the contents of this because of - the criticism, that there's been a pretty secretive deal.

Members of Congress can review this, but they have to go to a classified setting in the basement of the Capitol.

They can't take notes - or they can take notes, but they can't leave with their notes.

They can't talk about it publicly.

And we in the press certainly can't see it.

So it's really hard to judge it on the merits, other than hearing the talking points on both sides.

ED O'KEEFE: Meanwhile, from her perch in Brooklyn - (laughter) - sits Hillary Clinton, who has been virtually silent on this and certainly noncommittal.

I imagine there's a lot of frustration among the Democrats who want this and a lot of glee among the Democrats that don't that she, so far at least, has stayed out of it.

MANU RAJU: Yeah, she clearly wants this to be done with.

I think that would be the one thing that Hillary Clinton wants.

I mean, of course, her husband signed NAFTA into law.

She's been a pro-trade Democrat.

She voted - GWEN IFILL: When she was the secretary of State she thought this very idea was a - deal was a good idea.

MANU RAJU: Exactly, and she has now said, well, we need to see what the agreement is before she can support it.

And she's not weighed in on the issue before Congress right now, which is that fast-track authority, does she actually support the Trade Promotion Authority.

She has not said that explicitly.

Clearly, this is an effort to cover herself on the left, given the fact that she's trying to reach out to that Elizabeth Warren wing of the party right now.

And she doesn't want to come out for it because that would alienate those supporters she's trying to court.

GWEN IFILL: You've got to hate when politics gets in the way of policy, you know?

(Laughter.)

It really does.

All right.

Well, there's nothing like a deadly and shocking accident to focus the mind on an issue that was otherwise gathering dust on Capitol Hill: What is the state of Amtrak?

Can the publicly supported rail system be counted on to safely ferry the millions of travelers who get on board each year?

After a House committee approved a cut in Amtrak funding on Wednesday, the day after the crash, Democrats cried foul.

REPRESENTATIVE STEVE ISRAEL (D-NY): (From video.)

Last night we failed them.

We failed to invest in their safety.

REPRESENTATIVE STEVE ISRAEL (D-NY): (From video.)

We are divesting from America in this subcommittee - in this committee, and it doesn't make sense.

And it defies the interests of the American people.

GWEN IFILL: But if Amtrak's infrastructure is outdated, particularly in the busy Northeast Corridor, is there a fix?

There may be, but House Speaker John Boehner says it's not about money.

SPEAKER JOHN BOEHNER: (From video.)

The train was going twice the speed limit.

Adequate funds were there.

No money's been cut from rail safety.

And the House passed a bill earlier this spring to reauthorize Amtrak and authorize a lot of these programs.

And it's hard for me to imagine that people take the bait on some of the nonsense that gets spewed around here.

GWEN IFILL: Nonsense getting spewed again.

FAWN JOHNSON: I can't imagine it.

(Laughter.)

GWEN IFILL: I can't imagine it happening on Capitol Hill.

Where does the funding debate stand right now, Fawn?

FAWN JOHNSON: Well, it actually - I find it kind of amusing that there was so much passion being spewed over $300 million.

That's literally what the cut was that the subcommittee voted on the day after the accident.

It is true, though, if you see Steve Israel - GWEN IFILL: Which, by the way, by Washington standards is not a lot of money, OK. FAWN JOHNSON: That's not very much.

Sorry, I've been covering defense.

They talk about billions.

But if you can see the passion of Steve Israel in this particular case, you know, you can see that Democrats are very frustrated that - they tend to really like passenger rail.

They particularly like Amtrak.

And it has been underfunded for a really long time.

The thing that - the place to go forward from here, I think, there's a couple different things that you can do.

As the speaker noted, the House actually did pass an Amtrak authorization bill - so this is not funding directly, but it gives - it sets the cap - about a month ago.

And one of the things that it did was it said all of the money that is made along the Northeastern Corridor, which is the only place in Amtrak that's profitable, should stay there for investment.

There's a lot of places along the corridor that need a lot of help.

Anybody who rides it will probably be familiar with the bridge that goes over the Hudson River into New York.

GWEN IFILL: I never look out the window when we go across that.

FAWN JOHNSON: And, well, so this is a hundred-year-old bridge.

It would cost almost a billion dollars to renovate it and to fix it and to upgrade it.

So we're talking, you know, for the entire Northeastern Corridor, it's probably $20 billion just to do the sort of shovel-ready projects.

So this is why 300 million (dollars) is really not that big of a deal.

But there is this bill that passed, bipartisan, you know, there is - it's moving in the Senate.

That's one thing that they could do to help the train system.

But the problem, of course, is that even that bill is a status quo bill.

We're talking $1.4 billion for Amtrak, and what they need is 20 (billion dollars) or 30 (billion dollars).

ED O'KEEFE: But, you know, having traveled the country the last few months and delayed in planes and on bad highways and in trains and whatnot, I mean, this is part of a broader problem.

FAWN JOHNSON: Absolutely.

ED O'KEEFE: There has been no transportation infrastructure spending bill for at least five or six years now.

Why not?

These are the most frequent travelers in the country.

You would think they'd want to find a way to fix airports, highways, bridges, railways.

Why can't they do it?

FAWN JOHNSON: I have been asking the same question ever since I started covering transportation, and part of the reason is that they don't have what they used to have back in the heydays.

They don't have what they call earmarks.

So you're right, the last really long-term transportation bill that spent a lot of money was in 2005, and that was the one with the infamous Bridge to Nowhere.

And since then we've had huge budget cuts, obviously, and lawmakers can't direct money to their districts for individual projects, which means that - GWEN IFILL: It used to be called pork barrel.

All of a sudden it went out of fashion.

FAWN JOHNSON: Right.

And so - and then also keep in mind, again, it's that odd thing about Congress.

It doesn't have to do with transportation.

Everybody supports that.

But every time you spend money on transportation, you have to take money somewhere else.

And so even now, as we speak, this is starting to - even before this accident, this is starting to bubble up.

Just this week we're going to see the House vote on a transportation bill that's going to take us through July, and they're going to work on a long-term bill.

So it's getting there, but it's taking a really long time.

MANU RAJU: Republicans often say that, you know, you spend money on Amtrak and, you know, they squander that money.

Is that a fair criticism?

FAWN JOHNSON: It is a fair criticism.

One of the things that - I was going back and researching this - that the OIG - the inspector general found in FY '13 that Amtrak was operating with not sound business practices, meaning that every time they got money for something they would not contract correctly, they wouldn't get the best people to build whatever they needed, you know, cabs or - and they also - they are funded to make up for their operating losses, but every year they come to Congress and ask for about 1/3 more than they actually lose.

And members of Congress get a little irritated with that.

PETER BAKER: Well, is John Boehner right, though?

Is this a stupid question in the sense of is this train crash connected to this broader debate?

Was it human error, or should there have been these automatic, you know, speed controls that haven't yet been activated yet on the train?

GWEN IFILL: Braking.

FAWN JOHNSON: Well, and actually the fact that those speed controls were not enacted makes it not a stupid question because it takes a lot of money to get those things together.

It also takes a lot of research.

But the research and development is the place where sometimes they've been underfunding.

So yes.

GWEN IFILL: That much is expensive, exactly.

Well, we'll move on.

The week started off with what seemed like a snub when Saudi King Salman decided to skip a long-planned Gulf Cooperation Council meeting - summit at Camp David.

Six Gulf leaders did appear, and they had a lot to discuss, including the upheaval in Yemen and the looming Iran nuclear deal.

Was this merely hand-holding up at Camp David, or was there really substance underway, Peter?

PETER BAKER: Gwen, you say that as if hand-holding is somehow a bad thing, you know.

GWEN IFILL: It turns out that's an essential thing, right?

PETER BAKER: And actually, in diplomacy, hand-holding - and particularly in the Arab World, hand-holding is actually a storied tradition.

And yes, it was about hand-holding.

It was about the president saying to our allies there: Don't get nervous.

Just because we might be coming to a deal with Iran doesn't mean we're abandoning our traditional friends, who are very nervous about it.

Iran, of course, is a Shiite-led country.

These Gulf States are primarily Sunni-led countries.

They are at odds over many, many issues, and the nuclear deal just brings that tension to the table.

So having him bring them to his getaway - his presidential getaway, Camp David - was meant, if nothing else, as a symbolic gesture of support.

The tangible stuff is a little less so.

He said we have an ironclad commitment to their defense, but he wasn't willing to give them an actual security guarantee the way we give Japan or NATO or anything like that.

If you look at the actual document, it says if any Gulf State gets into security trouble, then we'll definitely sit down and talk about what to do about it, which is a little less than, you know, we're riding to the rescue.

And that's why some of these Gulf States were a little disappointed in what they got.

MANU RAJU: They came with a list of requests, didn't they?

And the mere fact that this meeting was held, does it signal that they really believe they're going to get a deal with Iran?

PETER BAKER: I think they do think there's going to be a deal with Iran.

Certainly in the White House they're feeling more optimistic lately than not.

Congress this week did pass the legislation allowing them to review the deal, but it doesn't seem to have knocked over the diplomatic possibilities.

That could have at one point been a real obstacle in sitting down with Tehran to finally work out in writing what they've agreed to in principle.

It doesn't seem to have done that.

So the administration's feeling somewhat optimistic that they can get to June 30, which is the deadline for finalizing this Iran deal, and make it happen.

So that's why the Arab states are watching this quite carefully.

MANU RAJU: To what extent do you think there will be a revolt from these Gulf leaders, assuming this deal is reached?

PETER BAKER: I mean, they're - you know, they're trying to see what they can get out of it, basically.

But there is a real danger here, and the danger is you hear, you know, talk of Saudi Arabia or some of the others getting into what they call an enrichment race with Iran: OK, you're going to allow Iran to enrich this much with this many centrifuges, we will match that.

Now, that doesn't mean necessarily an arms race, but you can see how it can easily then become one.

And that's something, obviously, the administration and its Western allies want to avoid.

FAWN JOHNSON: When the Congress is debating their Iran deal, when they were trying to - there were a lot of questions about how we can be ensured that whatever agreement Iran agrees to or decides - that we can hold it to them, that we can verify it.

I mean, they were really concerned about it.

Are those the same kinds of questions that come from these other Middle Eastern countries?

PETER BAKER: They do ask the same questions, exactly.

I mean, they don't trust Iran.

They have a lot of reasons not to trust Iran.

Iran has cheated many times before, and that track record doesn't give faith to the reassurances that this time will be different.

What the White House would say is, this is different, much like the trade deal is not NAFTA.

You know, we are building in assurances.

We are building an enforcement mechanism, in effect, much like they're saying with TPA, that will make this a different beast.

But as you say, in Washington there's not a lot of trust.

And frankly, in the Middle East region there's not a lot of trust.

GWEN IFILL: I wonder if we are not in a different negotiating position because the U.S. is less dependent on Middle Eastern oil.

On one hand, that should mean that we have more leverage to not force the issue, but get generally what the U.S. wants.

On the other hand, with a president who's about to end his term, with the perceived snub coming from Saudi Arabia and other friends, I wonder if the U.S isn't maybe at a disadvantage in these kinds of conversations now.

PETER BAKER: Well, we seem to have drifted apart from our old friends the Saudis, and it's not just the snub issue.

I mean, both sides say it wasn't a snub, but even if it wasn't intended as a snub it still came across as a sign of divergence in our interests.

And we do have energy independence increasingly now.

We're no longer as dependent on them.

And you know, the optics, as they say, weren't good.

The king of Bahrain chose not to come in order to go to a horse show in the U.K. with the queen.

That doesn't sound all that good.

And the president, when he sat down with the crown prince and the deputy crown prince from Saudi Arabia, who were sent in the king's stead, made a mistake and named the wrong king who had first met with FDR - GWEN IFILL: Hate when that happens.

PETER BAKER: - opening the era of U.S.-Saudi relations.

So there was kind of a - you know, you could see this disconnect on both a superficial level as well as a substantive level.

GWEN IFILL: But theoretically they are counting on the fact that shared interests trump all of this.

PETER BAKER: In the end that's the hope, yeah.

GWEN IFILL: OK. Well, thank you, Peter.

The Republican presidential field, already a crowded place.

But it was an as-yet-unannounced candidate who dominated the storyline this week.

It was not in the way Jeb Bush had intended.

Asked on Monday whether knowing what he knows now he would have gone to war in Iraq, this was his reply.

FORMER FLORIDA GOVERNOR JEB BUSH (R): (From video.)

I would have.

And so would have Hillary Clinton, just to remind everybody, and so would have almost everybody that was confronted with the intelligence they got.

GWEN IFILL: Mmm, Bush said he misunderstood the question.

Then he struggled with it some more before settling on this response Thursday.

JEB BUSH: If we're - if we're all supposed to answer hypothetical questions - knowing what we know now, what would you have done - I would have not engaged - I would have not gone into Iraq.

GWEN IFILL: It's always the hypotheticals that get you, or at least reveal how light you are or are not on your political feet.

Ed, you spent the week with Governor Bush.

How did this unfold?

ED O'KEEFE: You know, I think part of the problem here was he's been asked this question over and over again since he began traveling the country earlier this year.

The problem is he wasn't being asked that question on the Fox News Channel, which is a widely watched channel among Republicans, Megyn Kelly's show, one of their highest-rated.

The cameras were trained on him when he was asked a question he's been asked so many times before, and he stumbled.

He said he misunderstood it because knowing what you know now versus knowing what you knew then.

And what was most puzzling is it took him four days to sort of it out.

He could have done it Tuesday.

He could have done it Wednesday.

But it took him until Thursday.

And I think what you see is a man grappling with the desire to, as he puts it, campaign joyfully, which essentially means to campaign differently - to speak in nuance, to avoid looking at the past and talking more expansively about the future.

And his desire to do that ran into the realities of today, which is it's not how it works.

GWEN IFILL: When did it become a bad thing for a conservative to say that going to war in Iraq was a bad idea?

ED O'KEEFE: Well, it's happened over the last few years.

You look at the polling and roughly seven in 10 Americans, if not more, feel that the war was a mistake.

A majority of Republicans feel that way as well.

GWEN IFILL: And even, to his credit, George W. Bush has written as much.

ED O'KEEFE: Yeah.

I mean, he doesn't entirely regret his decision, but he admits that mistakes were made.

And that is the answer that Jeb Bush has given in the past: yes, mistakes were made, but the surge worked, my brother was politically courageous.

Seeing this opportunity, it was stunning to watch Republicans essentially violate the 11th Commandment, which says "thou shall not speak ill of another Republican."

Overnight, they did.

In fact, some did almost minutes after the speech or after the interview: Ted Cruz, Marco Rubio, Rand Paul, all - John Kasich, who's also thinking about running, very quickly making it clear they would not have done it, and putting distance between them and Bush.

Why are they doing this?

There is a growing concern or displeasure with the thought of a Bush running against a Clinton, all of these Republicans eager to distinguish themselves and become the anti-Bush candidate.

So they saw an opening and tried to take it.

PETER BAKER: You mentioned Hillary Clinton, and so did actually Jeb Bush.

This kind of reminds you of 2008, when her vote for the Iraq War was such a problem in her primary she tried various ways to explain it away.

What about this year?

Is that still an issue for her as she goes forward, or has she put that in the past?

ED O'KEEFE: It is, but her defenders point out, wait, she's already answered to this, did it in her book last year.

She had to do it over time on the campaign trail in 2008.

It was funny, there was a call yesterday for reporters with Democrats in Arizona because Bush was in Arizona, and they gave us their talking points on how awful this was and how Bush would be the third - Jeb Bush would be the third George Bush term and whatnot.

The only questions they got were about, well, what about Hillary Clinton?

There would be silence on the phone at first - (laughter) - as they tried to come up with an answer, and their basic answer was, well, she's explained it, she apologized.

This guy not only couldn't apologize it, but is being advised by people who helped put that war together.

If that doesn't bring you cause for concern, then what would?

MANU RAJU: I was going to say - sorry - Ed, Jeb has not been on the ballot for years.

There have been a lot of questions about his viability as a candidate, can he handle the spotlight.

How much concern is there in Bush world and among the donor class that he may not be ready for prime time, and that this could actually have a lasting impact?

ED O'KEEFE: Well, donors - and it comes as no surprise - are skittish.

When things are bad, they wonder if they put their money in the right place.

And they've been expressing that concern this week.

Bush world sees this, again, as a temporary stumble.

They point out, rightfully, that he has taken hundreds of questions from voters and from reporters since he started traveling the country in February.

GWEN IFILL: Which is more than you can say for - ED O'KEEFE: For anyone else, but especially Mrs. Clinton.

And that's the point he was making this week as well.

There was an exchange with a college student who confronted him on Iraq.

As uncomfortable as that might have been for him, as much of a moment it created for television, that's exactly the kind of exchange he wants to be having with voters.

He relishes the opportunity to do that.

And that's his plan, is to continue engaging - going to Iowa this weekend, New Hampshire next week, giving speeches and engaging Republicans across the country.

GWEN IFILL: Better now than later.

ED O'KEEFE: Exactly.

FAWN JOHNSON: So my question is, this blew up so much.

Does that suggest that Jeb Bush is the front-runner?

ED O'KEEFE: Well, yes, I think to some extent.

But I think it's also blown up because this is the kind of question he should have been prepared to answer, and he very clearly conveyed that he wasn't.

Whether or not his team was talking to him about it and trying to prepare him for this, that's unclear.

He's had this moment.

We'll see whether or not it sticks.

GWEN IFILL: Always better to have the moments early on.

ED O'KEEFE: Exactly.

GWEN IFILL: Unless you keep having them over and over again.

(Laughter.)

At which point it becomes a problem.

ED O'KEEFE: We'll be there waiting for them.

GWEN IFILL: OK.

Thank you, everybody.

We have to go now, but as always the conversation will continue online.

That's on the Washington Week Webcast Extra, which we'll post online later tonight and all week long at PBS.org/WashingtonWeek.

Among other things, we'll talk about the foreign policy debate breaking out on the campaign trail.

Keep up with developments with me and Judy Woodruff on the PBS NewsHour and we'll see you here next week on Washington Week.

Good night.