PETE WILIAMS: Sharp elbows in the Empire State as Hillary Clinton and Bernie Sanders jostle to make it there, while Donald Trump says Republican Party rules aren't on the level.

I'm Pete Williams in for Gwen Ifill tonight on Washington Week.

(Begin video segment.)

SENATOR BERNIE SANDERS (I-VT): I am sure a lot of people are very surprised to learn that you supported raising the minimum wage to 15 bucks an hour.

(Cheers, applause.)

FORMER SECRETARY OF STATE HILLARY CLINTON: You know, wait a minute, wait a minute.

SENATOR BERNIE SANDERS (I-VT): That's just not accurate.

HILLARY CLINTON: Wait, wait, come on.

(End video segment.)

PETE WILLIAMS: Clinton and Sanders clash as New York prepares to vote.

SENATOR BERNIE SANDERS (I-VT): (From video.)

Does Secretary Clinton have the experience and the intelligence to be a president?

Of course she does, but I do question - (cheers, applause) - but I do question her judgment.

HILLARY CLINTON: (From video.)

This is a phony attack that is designed to raise questions when there is no evidence or support to undergird the insinuations that he is putting forward in these attacks.

(Cheers, applause.)

PETE WILLIAMS: While on the Republican side, Donald Trump says Ted Cruz and the Republican establishment aren't playing fair.

DONALD TRUMP: (From video.)

It's a rigged system, folks.

The Republican National Committee, they should be ashamed of themselves for allowing this kind of crap to happen.

SENATOR TED CRUZ (R-TX): (From video.)

Donald has been yelling and screaming, a lot of whining.

PETE WILLIAMS: And the speaker of the House says this time he really means it.

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

Let me be clear: I do not want, nor will I accept, the nomination for our party.

PETE WILLIAMS: Our coverage of the presidential nominating march continues with Ed O'Keefe, political reporter for The Washington Post; Jonathan Martin, national political correspondent for The New York Times; Michael Scherer, Washington bureau chief for TIME Magazine; and Alexis Simendinger, White House correspondent for RealClearPolitics.

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, sitting in for Gwen Ifill this week, Pete Williams of NBC News.

PETE WILLIAMS: Good evening.

The first song ever broadcast by radio was performed onboard a ship docked at the Brooklyn Navy Yard.

It was called I Love You Truly.

Last night, there was anything but love in the air in Brooklyn as Hillary Clinton and Bernie Sanders met in that spot for their first debate in five weeks.

She was hoping to end his recent string of seven straight victories; he set the tone with his first answer about whether she's qualified to be president.

SENATOR BERNIE SANDERS (I-VT): (From video.)

I question her judgment about running super PACs which are collecting tens of millions of dollars from special interests, including $15 million from Wall Street.

(Cheers, applause.)

I don't believe that that is the kind of judgment we need to be the kind of president we need.

HILLARY CLINTON: (From video.)

Well, the people of New York voted for me twice to be their senator from New York.

(Cheers, applause.)

And President Obama trusted my judgment enough to ask me to be secretary of state for the United States.

(Cheers, applause.)

PETE WILLIAMS: There were candidates talking amid all that applause from the crowd.

But why did it seem so much more acrimonious last night?

ALEXIS SIMENDINGER: Well, in some ways, the stakes are higher.

Obviously, Bernie Sanders is thinking that Tuesday's primary in New York could be the end for him, definitely the end by the end of this month.

The Clinton campaign is talking about how he'll run out of real estate by the end of this month in terms of the number of delegates he would need to catch up to her.

The other element of it for Secretary Clinton is they're just sick of each other.

This has gone on longer than she anticipated or her team anticipated.

And he's out-raised her, he has dogged her.

He is not going to quit, he keeps going.

And yet her argument is that, you know, mathematically he just can't get the nomination, even if he claims the momentum.

And you can see also from the Democratic perspective it wasn't supposed to be like this because it's supposed to be a contrast with the Republicans.

This was too much of a reminder of what the Republicans are doing, as far as some Democrats.

Maybe not in New York, but for some.

MICHAEL SCHERER: One of the things that struck me is it's almost like there were two races being run last night.

There's the race for delegates, which Bernie Sanders is losing and Hillary is winning and almost certainly will win.

But there's this other race between them about how far left he could push her.

And every time she moved a little bit, he seemed to celebrate and get the crowd going and say, look, see, I did that, she said $15 an hour minimum wage instead of 12 (dollars) she used to say before.

Or when asked about the living wills, she said, yes, you should break up the banks.

These are positions that I don't think Hillary Clinton when she started this race wanted to be taking or expected to be taking at this point.

It's not that she wouldn't be happy if they came true but, you know, she's created a very modulated campaign so far.

PETE WILLIAMS: Let me ask you about this minimum wage thing because, you know, he said he wants it 15 (dollars), she said let's go 12 (dollars), step at a time.

Does that sort of illustrate the difference between his idealism and her pragmatism?

JONATHAN MARTIN: Absolutely.

It's a vivid illustration of that, Pete.

And you know, she's looking at the art of the possible and he is sort of totally consumed by what the world should be and perhaps not is.

And that's always been sort of the knock on her and more the Clinton brand.

They're for incrementalism.

And they've been unapologetic about that fact.

And as Michael mentioned, she's having to now try to remake herself into something different that is in contrast to that Clinton brand and sometimes it isn't a good fit and it can be perceived as a bit of a stretch.

But it's a reflection of today's Democratic Party that that's what she has to get to.

She doesn't have a choice in the matter, Pete.

She has got to accommodate a party that is very different today than it was when Bill Clinton ran, you know, '92.

PETE WILLIAMS: Ed, is there any sign that Bernie Sanders is expanding his base or is he basically the same place he's been all along?

ED O'KEEFE: No, it seems to be sticking to where it's been.

I think they had some hope in New York, given that two years ago there was a primary in the governor's race there and a liberal opponent challenged the sitting governor, Andrew Cuomo, and there was a belief that he could at least hit the 35 percent or so that she got and maybe expand upon it.

But if you look at poll after poll after poll, he hasn't really moved the needle and she's likely to get this race with at least 60 percent support.

ALEXIS SIMENDINGER: And he also addressed during the debate, he had this interesting retort about the South, the conservative South, which was stunning to some Democrats who believe that he was just absolutely walking away from the idea of wooing African-American voters in New York or anywhere else by dismissing his massacre in the South as, you know, this problem of conservatism when, you know, that's not necessarily true among Democrats.

So it was an odd thing to say.

MICHAEL SCHERER: A problem for Bernie from the beginning, it was clear - I mean, this is a guy who marched, who fought for civil rights as a college kid in Chicago, you know, who came to Washington and marched with Dr. King.

And yet, every step of the way this whole campaign when he has had to reach out to not the Vermont people he's used to dealing with, you know, the rest of the Democratic Party, he stumbles like this, he just hasn't been able to make the transition.

PETE WILLIAMS: One of the surprising moments, I thought, in the debate came on the subject of the Middle East, of Israel.

This is a state where that issue is more important than anywhere else.

Bernie Sanders said that Hillary Clinton hasn't done enough to support the Palestinians.

SENATOR BERNIE SANDERS (I-VT): (From video.)

I read Secretary Clinton's statement, speech before AIPAC.

I heard virtually no discussion at all about the needs of the Palestinian people, almost none in that speech.

HILLARY CLINTON: (From video.)

I'm the person who held the last three meetings between the president of the Palestinian Authority and the prime minister of Israel, three long meetings, and I was absolutely focused on what was fair and right for the Palestinians.

PETE WILLIAMS: So was that a risky thing for Bernie Sanders to do in New York?

JONATHAN MARTIN: Well, speaking of how politics have changed in their party, imagine dropping Ed Koch and Pat Moynihan back into that primary last night, the debate last night.

I mean, they would be shocked about what's happened to the politics of their party in their state.

The fact is that what Bernie did last night wasn't that risky.

He's probably not going to do that well with Jewish voters who are most passionate about Israel.

They are either, A, Republicans; or, B, they're voting for Hillary Clinton.

What he is doing is speaking to a new generation of progressives.

That it is much more, I guess, evenhanded is the phrase when it comes to looking at Israel.

But it does speak to how the politics on the issue have changed.

Is it risky for him?

Not really, given where his voters are and where the party is now.

ED O'KEEFE: Well, what was also ironic about it is remember when she ran for the Senate she got attacked for having met with and I think embraced the wife of Yasser Arafat when she was visiting the United States.

JONATHAN MARTIN: Sixteen years ago, yeah.

ED O'KEEFE: Right.

And she had to sort of distance herself from the Palestinians.

PETE WILLIAMS: Yeah, great point.

ED O'KEEFE: So now be told that she's not doing enough for the Palestinians, it must have been such a circle of life moment for someone who began her career in New York and is hoping to solidify her career by going back to New York.

PETE WILLIAMS: So they both left town immediately after the New York debate, Bernie Sanders to Rome.

What was the political thinking there?

ALEXIS SIMENDINGER: Of course, if there's a primary on Tuesday you would go to Rome, too, right?

(Laughter.)

Actually, Senator Sanders got an invitation he said he just couldn't pass up, which was to participate in a conference in Rome that dealt with issues, it's almost like a think tank kind of discussion about the issues he cares so much about, you know, the morality of our economy and what we should do as a society, as a world, a globe.

And he took his entire family, his grandchildren, and he went there.

Where Secretary Clinton went?

She went to California.

Why?

She's raising money and she's spending time with Hollywood types like actor George Clooney and his wife, and doing some events, looking ahead to the contest in June in California.

So they'll return to New York, but each of them took a break.

PETE WILLIAMS: Well, 10 months into his campaign for president, Donald Trump has become preoccupied with the Republican Party's rules for choosing its delegates to the national convention.

But he's getting no sympathy from Ted Cruz or the party's national chairman.

DONALD TRUMP: (From video.)

I have millions of votes more, but I also have hundreds of delegates more, but that's not the same thing to me.

I think the vote is the thing that you count, right?

The vote.

DONALD TRUMP: (From video.)

I know the rules very well, but I know that it's stacked against me by the establishment.

SENATOR TED CRUZ (R-TX): (From video.)

Anyone who knows anything about Washington knows that the establishment is not rooting for me.

But the rules are simple.

The way you get elected is that you win a majority of the delegates in election.

REINCE PRIEBUS (RNC Chairman): (From video.)

The delegates are empowered by the voters, but the delegates on the floor choose the nominee of the party after being empowered by the voters.

This is a very normal system that we've been using for many years.

PETE WILLIAMS: So, Ed, two questions here.

First of all, does Donald Trump have a point?

And secondly, why the public campaigning and complaining about it?

ED O'KEEFE: Well, I think, you know, he's making a political point in order to keep his base motivated in the few states that remain and to keep his supporters motivated in the states that have already voted, urging them to turn out to their delegate processes if they're allowed to show up.

You know, he - I had a senior Republican Party official today describe it this way, and I think it's a very good idea, a good way to frame it.

It's as if he is the owner of an NFL expansion team who is complaining about, you know, how field goals are kicked and accusing the league of conspiring against his team to lose.

And it's, like, no, if you just learn the rules of the game you'll understand they're not actually there to conspire against you, it's just the way it is.

And he - you know, the Colorado situation he's been complaining about is probably the most democratic, small-D democratic, process.

PETE WILLIAMS: And very quickly, what is that?

What happens?

ED O'KEEFE: They use a convention that was last Saturday, that is the culmination of four or five months of precinct meetings, district meetings, county meetings, congressional district meetings where thousands of Republicans across the state came together at one point or another to pick the 34 people who will represent them in Cleveland at the convention.

It is probably the messiest, most chaotic and somewhat romantic version of democracy you can find in this country.

It's just that it's not a primary or caucus where someone will sit there on a Tuesday night and tell us who won.

JONATHAN MARTIN: And it was well-known, by the way, that they had made the change last year - ED O'KEEFE: Right.

JONATHAN MARTIN: - Colorado had.

It actually became quite a story in the political universe that they had gone from a caucus to a convention.

It was very, very well-known.

I think Trump, Pete, is also playing a psychological game here.

He is starting to set up what is effectively going to be a pressure campaign on the group of unbound delegates.

These are the folks who are going to the convention who are not going to be committed to any of the candidates, who are basically political free agents.

I think this is the start of a campaign to them for Trump to say I'm going to have the most delegates and the most votes, I might be short of a majority, but you can't deny me this.

And I think he is setting that up by what he is doing right now.

ALEXIS SIMENDINGER: One of the ironies of this, though, for those who are inside the Republican Party is that the folks he needs to woo to win over, they're part of the party - JONATHAN MARTIN: Yeah, they are the party, yeah.

ALEXIS SIMENDINGER: They are the party.

They're the infrastructure.

So by doing what Ed is saying, which is the art of the deal of negotiating with your base, isn't going to help you in the same way that it would if you were, you know - stiff-arming the RNC is not the way to go.

MICHAEL SCHERER: I think it's also becoming increasingly clear that Trump may just have one shot at this on the first ballot.

JONATHAN MARTIN: Yeah.

ED O'KEEFE: Well, he only has one, yeah.

MICHAEL SCHERER: Because there's two delegate fights going on right now.

There's what happened in Colorado, which is actually choosing delegates who get to choose who they will support at the convention, and then there's a separate fight of choosing delegates to support Donald Trump at the convention on probably just the first ballot, sometimes the first and the second ballot.

And Cruz has been incredibly effective and other party establishment figures in different states have been incredibly effective of seeding that pro-Trump pool with anti-Trump people.

So if Trump is not able to lock them up on the first ballot, those people are very eager to run away from him.

PETE WILLIAMS: Well, go ahead.

ED O'KEEFE: Well, it was just stunning this week to see his new senior adviser, this guy, Paul Manafort, tell me, look, it's irrelevant - PETE WILLIAMS: Whose new senior adviser?

ED O'KEEFE: Trump's new senior adviser, say, look, the fact that Ted Cruz is packing these delegate slots with is supporters who would switch on a later ballot is irrelevant because we're going to get 1,237.

JONATHAN MARTIN: Yeah, that's the gamble.

ED O'KEEFE: But if we do get to a later round, he sort of surmised we're screwed.

(Laughter.)

PETE WILLIAMS: I want to ask you about the piece you wrote about Ted Cruz.

MICHAEL SCHERER: Yeah.

PETE WILLIAMS: Is Ted Cruz becoming more mainstream?

If Hillary Clinton's moving more to the left, is Ted Cruz moving more to the center?

MICHAEL SCHERER: He's certainly singing a different song, whether it will be successful in wooing a different crowd is very much an open question.

He's not a very talented or tested politician in appealing to the middle.

This is a guy whose entire brand is always going to the right on every question.

And you know, if you compare what he was doing in Iowa, which was talking every day about churches who are oppressed by gay people who are coming and trying to get married in their churches, to what he's saying now on the stump or every time he's interviewed, he talks about raising wages, getting people back to work, manufacturing jobs in America.

I mean, he's speaking as if he's a Democrat now.

He's speaking that moderate, middle-of-the-road - PETE WILLIAMS: Why?

MICHAEL SCHERER: Because he's trying to convince his party in the short term that he can actually carry this in the general election.

And that's something that, you know, his party, for the most part, at least the elected part of his party, doesn't like him at all because he is - JONATHAN MARTIN: That's safe to say, yeah.

(Laughter.)

MICHAEL SCHERER: Yeah, because he has - his career has been based on basically stepping on members of his own party to push himself ahead.

And so he has to convince them and he has to convince the rank and file that he's not just far-right Ted, that he can actually create a challenge for Hillary Clinton.

PETE WILLIAMS: So speaking of votes, tell me, Ed, about the Trump arithmetic.

So how does winning New York change the future path to 1,237 for Donald Trump?

ED O'KEEFE: So there are 95 delegates up for grabs Tuesday night in New York.

You get a chunk if you win statewide and you get a chunk in each congressional district.

Across the country, Republicans assigned three delegates to each of the 435 congressional districts.

Every state does it one of a few ways.

In New York it's essentially if you get more than 50 percent you get them all.

If you don't get more than 50 percent in the district, it probably goes to a two-to-one split between Trump and somebody else.

There are a few districts, mostly around New York City, that are unlikely to be 50-percent-plus for Trump, on Long Island, Westchester County and some of the ones right in the city.

They might go to John Kasich most likely.

So he won't get 95 probably.

If that's the case, he needs to continue to do well and win overwhelmingly or, you know, supermajorities in Pennsylvania later in the month, in Maryland, in Rhode Island, Connecticut and Delaware.

PETE WILLIAMS: Those all look good for him, don't they?

ED O'KEEFE: They do because his brand of Republicanism does very well in the Northeast and the Mid-Atlantic.

John Kasich's not running a serious campaign in those places and Ted Cruz is anathema because he's a conservative from Texas to most of those Republicans.

JONATHAN MARTIN: Yeah.

And the challenge for Trump is that every delegate counts now.

And so you take Pennsylvania, for example, well, there are a handful of delegates available statewide, but actually most of them are unbound.

Rhode Island, it's more proportionally done.

This is all inside baseball, Pete.

But what it adds up to is every state, as Ed said, has its unique structure of allocating delegates.

And for the ones where Trump looks to be the strongest, very few of them are winner-take-all.

Meaning that even in the states where he wins, he's not going to get every single delegate.

ED O'KEEFE: And that's the irony of Cruz's sort of anti-establishment message.

He may rail against the Washington establishment, but what this process is beginning to expose is that he has wooed and has won over the political establishment in places like Colorado Springs - JONATHAN MARTIN: Yeah.

ED O'KEEFE: - Topeka, Kansas - MICHAEL SCHERER: The activists, yeah.

ED O'KEEFE: - Augusta, Georgia, the rank and file councilmen and precinct captains - JONATHAN MARTIN: Yeah.

Yeah, right.

ED O'KEEFE: - who are going to stuff those delegate slots with people who would vote for him.

PETE WILLIAMS: So, Alexis, does Donald Trump have a chance, is it looking like he will win the nomination on the first ballot?

ALEXIS SIMENDINGER: Oh, I think it's not possible to even exactly say that right now.

Why would we know that right now?

There's so many of these important big states to go.

And, you know, where is he now?

He's a little over 700, you know, and he's got a long way to go.

MICHAEL SCHERER: Yeah.

The other thing to take into account is, because of these unbound delegates, if he gets within 20, 30, 40, he doesn't have to actually hit that number exactly, there's a very good chance.

Because at that point he's going to be threatening the whole party that if you don't put me in this position - JONATHAN MARTIN: I'm walking off now.

MICHAEL SCHERER: - I'm walking and I'm going to take all my people and you will lose the general election, and that will be pretty compelling.

PETE WILLIAMS: OK.

I want to ask you about one other development this week that was interesting.

Paul Ryan invoked the words of Civil War General William Tecumseh Sherman who famously said I will not accept if nominated and will not serve if elected, insisting that he absolutely, positively does not want to become a candidate for president at a contested convention.

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

I simply believe that if you want to be the nominee for our party to be the president, you should actually run for it.

I chose not to do this.

Therefore, I should not be considered, period, end of story.

PETE WILLIAMS: But his effort to end the story was complicated by this video released by the speaker's office challenging America to come together.

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

So let's have a battle of ideas, let's have a contest of whose ideas are better and why our ideas are better.

PETE WILLIAMS: So Jonathan, Ryan also had a news conference to talk about his trip to the Middle East.

And this sort of reminds me of the Groucho Marx line, who are you going to believe, me or your lying eyes?

(Laughter.)

JONATHAN MARTIN: There are similarities there.

It was striking to me that he once again said he is not running, not via a press release on a piece of paper, but instead in front of the cameras with four flags behind him.

Look, he does not want to run, but what he does want to do, Pete, is establish himself as a sort of counter to Trump.

He wants to be somebody who is carrying a different banner of conservatism than Trump's kind of grievance style of politics.

And so that's what he's doing here.

One fast point.

What was striking to me about that press conference was the fact that he denounced the general concept of a white knight coming in to save the day who hadn't run before.

Not just the fact that it wouldn't be him, he said nobody should even try and do that, and that sort of douses the blanket further on that possibility.

ED O'KEEFE: And reflects polling data that shows most of the party agrees him.

JONATHAN MARTIN: Don't want it, yeah.

ED O'KEEFE: I'll say one thing.

This idea that that glossy videoed signaled something.

Look, if you've spent time on Capitol Hill, you know the same guy who produced that video for Paul Ryan was producing those same kind of glossy videos for John Boehner back in the day.

This is nothing new.

It's just what we have - PETE WILLIAMS: His timing is everything.

ED O'KEEFE: Right.

Well, we're all - PETE WILLIAMS: So there was a little pushback on this from people who said, you know, it's not for you to make this decision.

Eisenhower once said that Americans don't - the same sort of thing came up - Americans don't have the right to say categorically that they will not perform any duty that their country might demand of them.

So are the Republicans saying this about Paul Ryan?

MICHAEL SCHERER: Look, there was only ever one scenario in which Paul Ryan would really get the nomination, and that is if everyone else who had been running fails to get the nomination.

This would be on the eighth or ninth or 10th ballot.

That still exists as a possibility.

PETE WILLIAMS: Yes.

MICHAEL SCHERER: If we go through that convention - PETE WILLIAMS: We can dream about that, I'm sure.

MICHAEL SCHERER: We can dream.

It's not going to happen.

(Laughter.)

JONATHAN MARTIN: Forty-seven ballots on Labor Day.

(Laughter.)

MICHAEL SCHERER: Right.

But if everyone else fails, I think Paul Ryan's calculation here is that, look, this has been a very difficult year for Republicans, this is probably going to be a very difficult general election for Republicans.

And he's got a longer view.

He's a young guy, he can run in 2020, he can run in 2024.

I mean, he's got lots of years ahead of him.

And more importantly, he right now really is the face of Republicanism that is not in this race.

And I think he's preparing himself to be able to pick up the pieces no matter what happens.

PETE WILLIAMS: But very briefly, let me ask you for a quick answer.

He's going to be the chairman of the convention, though, right?

Does that give him any power, or does he just say hello and goodbye?

ED O'KEEFE: No.

Well, most years that would be the case if there wasn't a contested convention.

But this year he's actually going to sit there with the gavel and have to sort things out.

There may be motions from the floor.

There may be other disputes to settle, and he'll have to do that.

PETE WILLIAMS: But he doesn't have any behind-the-scenes role here?

He's - ED O'KEEFE: Oh, he could, absolutely.

PETE WILLIAMS: He's not the kingmaker.

ED O'KEEFE: He won't be the kingmaker necessarily, but he is the one that might tell the campaigns get your act together and let's settle this on the next ballot.

JONATHAN MARTIN: He'll have a voice, yeah.

MICHAEL SCHERER: And one of the interesting dramas here is, like, normally the convention is designed by the candidate in waiting, right?

And we're going to probably be going into a convention - JONATHAN MARTIN: With no candidate in waiting.

MICHAEL SCHERER: - without a candidate in waiting.

So you know, Reince Priebus is going to be pricking the drapes and figuring out, you know, what's on the - ALEXIS SIMENDINGER: The stage, the program.

MICHAEL SCHERER: Everything.

ALEXIS SIMENDINGER: Yeah.

MICHAEL SCHERER: And Ryan will be sitting next to Reince.

I think the chairman of the Republican Party is going to have an enormous amount of power.

And the extent to which they work together, both from Wisconsin, they're old friends, they know each other very well, Ryan will definitely have a say.

PETE WILLIAMS: So he'll be - this is his audition then?

ED O'KEEFE: Some would say.

(Laughter.)

PETE WILLIAMS: All right.

JONATHAN MARTIN: Dick Cheney-esque, right?

PETE WILLIAMS: All right.

(Laughter.)

No comment, that'll have to wrap it up for tonight.

But be sure to check out the Washington Week Webcast Extra, where Michael will tell us the impact that the Broadway hit Hamilton is having on the United States Treasury decision to remake the $10 bill.

That's at PBS.org/WashingtonWeek, later tonight and all weekend long.

Be sure to keep up with daily developments on the PBS NewsHour, and look for us around the table again next week on Washington Week.

I'm Pete Williams.

Good night.