GEOFF BENNETT: Good evening.

I'm Geoff Bennett.

AMNA NAWAZ: And I'm Amna Nawaz.

On the "NewsHour" tonight: Smoke from Canadian wildfires blankets wide swathes of the Eastern United States, causing air quality concerns for millions of Americans.

PETER DECARLO, Johns Hopkins University: The high levels of air pollution are going to be detrimental to people who are at risk.

But, really, everyone is impacted by this.

GEOFF BENNETT: Rescuers rush to get civilians to safety in Southern Ukraine after a catastrophic dam breach floods streets and buildings.

AMNA NAWAZ: And the Republican presidential field expands, with former Vice President Mike Pence and North Dakota Governor Doug Burgum announcing their bids for the White House.

(BREAK) AMNA NAWAZ: Welcome to the "NewsHour."

Hundreds of wildfires continue to burn across Canada, many of them out of control.

GEOFF BENNETT: The smoke has more than 55 million Americans under air quality alerts, prompting safety warnings to stay indoors and the cancellation of some major events, including professional baseball and basketball games.

Stephanie Sy has our report.

STEPHANIE SY: An ominous orange haze envelops the Statue of Liberty.

Wildfire smoke from Canada has billowed across the border, degrading air quality across the Northeast and Upper Midwest.

Pilots and passengers flew through thick clouds of black smoke, before the FAA temporarily grounded flights out of New York.

SAMUEL GARCIA ANGEL, New York Tourist: It's very unexpected.

Like, it really happened out of the blue.

And I just really hope that everyone stays safe, wear a mask outside, so the smoke doesn't go into their lungs.

STEPHANIE SY: Today, the Big Apple ranked worst in the world for its air quality.

New York City Mayor Eric Adams issued health advisories for all five boroughs.

ERIC ADAMS (D), Mayor of New York: This is an unprecedented event in our city, and New Yorkers must take precaution.

STEPHANIE SY: As wildfire smoke continues to blanket the U.S., 100 million Americans are under air quality alerts, the potential health threat posed by wildfire smoke spanning as far south as Georgia and Texas.

PETER DECARLO, Johns Hopkins University: The high levels of air pollution are going to be detrimental to people who are at risk.

But, really, everyone is impacted by this.

STEPHANIE SY: Peter DeCarlo is an associate professor of environmental health and engineering at Johns Hopkins University.

PETER DECARLO: Exposure to air pollutants isn't something you can undo.

These are particles that are about 100 times smaller than the width of our hair.

When we breathe those in, they get into our lungs.

They can basically travel to all parts of our body.

And so we usually think of the respiratory system as the most impacted.

But this also impacts our heart.

It can impact our brain.

STEPHANIE SY: In Canada, more than 20,000 Canadians can't go home, still under evacuation orders, as firefighters struggle to contain hundreds of wildfires.

BRENT JOHNSTON, Nova Scotia Evacuee: Fortunate enough to have a trailer right now that we could get out for the time being.

STEPHANIE SY: In British Columbia, this crew is fighting fire with fire, burning out fuel ahead of an approaching blaze.

Canada's minister of public safety says there are 414 active fires across the country; 239 are out of control.

BILL BLAIR, Canadian Minister of Public Safety: I want to assure Canadians that all orders of government are working closely together, including with our indigenous partners, to ensure a coordinated and effective response.

It's all hands on deck and it's around the clock.

STEPHANIE SY: Coast to coast, forest fires have scorched more than 9.1 million acres in Canada already this year, an area bigger than the state of Maryland.

And it's just the start of what is on track to be the most devastating fire season in Canada's history.

KRISTINA DAHL, Union of Concerned Scientists: The fact that we're seeing so many fires burning such large areas and burning this early in the season is definitely worrisome STEPHANIE SY: Climate scientist Kristina Dahl says several factors at play.

KRISTINA DAHL: We know that climate change isn't the only factor that's at play in driving worsening wildfires around the world.

We know that things like suppressing fires for many decades or even a century can cause a lot of undergrowth in our forests to build up that would have been naturally cleared by naturally occurring fires and low-severity fires.

But now that we have been suppressing those fires, we have a lot of overgrowth.

And that's causing fires to burn larger and more severely.

STEPHANIE SY: As firefighters try to contain the fires across Canada, officials in many U.S. cities warn, air quality is at Code Red.

It is not the highest alert level, but it does mean the air may be unhealthy for some and outdoor activity is discouraged.

For the "PBS NewsHour," I'm Stephanie Sy.

AMNA NAWAZ: In the day's other headlines: A former top aide to President Trump, Taylor Budowich, testified before a federal grand jury about classified documents at Mr. Trump's Florida estate.

On Twitter, Budowich said -- quote -- "I fulfilled a legal obligation to testify and I answered every question honestly."

The new grand jury is separate from a panel in Washington.

Both are reportedly investigating Mr. Trump's handling of classified material recovered from his Mar-a-Lago home.

A teenager in Richmond, Virginia, was arraigned today in a shooting that killed two people and wounded five just after a high school graduation.

Tuesday's attack left families stunned and police trying to restore order.

The interim police chief says the 19-year-old suspect singled out one of the new graduates.

He was killed, along with his father.

RICK EDWARDS, Richmond, Virginia, Interim Police Chief: This was targeted at one individual.

And so they knew each other and had an ongoing dispute.

That's the -- that's what we know at this time.

But, again, as I said, this is still a fluid situation.

We're hours into the investigation and well learn more as we go.

AMNA NAWAZ: The accused gunman is charged with second-degree murder and is being held without bond.

A white woman in Ocala, Florida, is now charged with killing a Black neighbor Ajike Owens in a case that brought demands for action.

Owens was fatally shot in a Friday night confrontation.

Last night, Susan Lorincz was charged with manslaughter.

The local sheriff says it took time to review her claim of self-defense.

BILLY WOODS, Marion County, Florida, Sheriff: When we do these investigations of cases of this level, rushing in to make an arrest is not the right thing to do sometimes.

My detectives cannot complete an investigation without getting all sides of the story.

And, that night, all we had was one person's story, and that was the shooter's story.

AMNA NAWAZ: Lorincz had said she fired through her front door when Owens tried to break it down.

The sheriff said, ultimately, investigators found it was not a stand-your-ground case, but, in his words -- quote -- "simply a killing."

In Rome, Pope Francis is recovering tonight after undergoing abdominal surgery.

The pontiff left for the hospital earlier today.

His doctor said the three-hour operation repaired a hernia apparently caused by colon surgery in 2021.

DR. SERGIO ALFIERI, Surgeon (through translator): The surgery and general anesthesia went off without complications.

The Holy Father reacted well to both the surgery and the anesthesia.

The Holy Father is already awake.

He has already joked around and teased me.

AMNA NAWAZ: Pope Francis is 86 years old.

He's expected to remain hospitalized for several days.

Back in this country, a school board in Southern California has voted to designate June as Pride Month after supporters and opponents came to blows.

People on both sides gathered Tuesday evening outside the Glendale School District headquarters.

Tempers flared and a fight erupted in the parking lot with people punching and tackling each other.

Police quickly moved in to break up the brawl and clear the area.

CNN has fired its embattled CEO, Chris Licht, after just a year on the job.

He had vowed to bring the cable network closer to the political center, but ratings and revenues sagged.

The final blows may have been a scathing profile in "The Atlantic" following a widely criticized live town hall with former President Trump.

And Wall Street had a mixed finish, as losses by big-tech stocks weighed down the market.

The Dow Jones industrial average gained 91 points to close at 33665.

But the Nasdaq fell 171 points, or 1.3 percent.

The S&P 500 slipped 16 points.

Still to come on the "NewsHour": how police officers' words in the first seconds of a traffic stop affect the outcome for Black drivers; a new role on theater and film sets aims to ensure safety in intimate scenes; a statue of Pulitzer Prize-winning novelist Willa Cather is unveiled in the U.S. Capitol; plus much more.

GEOFF BENNETT: Floodwaters are inundating parts of Southern Ukraine and rescue and relief efforts are under way, as the waters keep rising.

Yesterday's dam collapse has unleashed humanitarian and ecological disasters in a nation already suffering from 16 months of war.

Evacuations continuing today after the Ukraine dam disaster, as the scope of devastation comes into full view.

Drone footage showed rooftops barely holding above rising water lines, some swept away entirely by the Dnipro River, as floodwaters engulfed village after village in Southern Ukraine.

VALERY MELNIK, Ukraine Resident (through translator): It is our home where we live.

Or it was.

Maybe it will be again when it dries out.

GEOFF BENNETT: Flood victims in Kherson sifted through their belongings, desperate to save pets from drowning, and to salvage soiled items.

Earlier today, Ukrainian authorities said the river was still swelling and water levels could remain at peak heights for as long as 10 days.

Evacuation efforts were swift.

Residents joined Ukrainian police as they navigated the streets on inflatable boats and makeshift rafts, even as the sounds of nearby shelling persisted.

MYKHAILO SMITSKII, Volunteer Rescuer (through translator): I have been coming here for a whole year.

I want to do something useful for our country, for our people.

GEOFF BENNETT: So far, about 3,000 people have fled their homes, but over 60,000 people reside in the flood-impacted areas.

The exact cause of yesterday's breach is still undetermined.

Both Ukraine and Russia have accused each other of deliberate attacks, while others say Russian attacks on the dam last year could have caused cracks that led to its collapse over time.

Security footage from November showed a fiery blast tearing through a section of the dam's walls.

This satellite image from June 1 shows the dam intact, on June 2, clear damage to a section of road.

And, by yesterday, June 6, the dam was completely destroyed, with water bursting through.

As the Kakhovka Reservoir empties downstream, the humanitarian implications are immense.

Ukrainian officials warn that floating mines unearthed by the deluge pose a threat to civilians across the region.

And as a critical source of drinking water is cut off, experts fear the spread of diseases and hazardous chemicals.

DENYS SHMYHAL, Prime Minister of Ukraine: Dozens of towns and villages will struggle with the issue of potable water supply.

The destruction of the Kakhovka hydroelectric power station is a crime against humanity and an ecocide.

GEOFF BENNETT: All this on top of a relentless war.

For an update on the ongoing rescue and relief efforts, we turn to Ewan Watson.

He's the head of communications at the International Committee of the Red Cross.

He joins us now from Geneva.

Thank you for being with us.

How is the ICRC, the Red Cross, assisting with the ongoing rescue and relief efforts across Southern Ukraine?

What are you hearing from your partners on the ground?

EWAN WATSON, International Committee of the Red Cross: Well, our partners, the Ukrainian Red Cross, are doing incredible work right now.

So, on day one, they already managed to evacuate 800 people, including approximately 60 people with low or absolutely no mobility at all.

You have got to remember that, in this flood-stricken area, this was already an area that was devastated by fighting.

So, many people have fled.

And many, many of the people that remain are people that were sick, who were old, who couldn't really -- couldn't really go anywhere.

So they were desperately vulnerable already, before this dam was destroyed.

And here we are with yet another tragedy on our hands.

So, what we have been focusing on through our partners, the Ukrainian Red Cross, is really to move people to a degree of safety.

Of course, people are alarmed, shocked by the rapidity of the rising water.

It's obviously extremely dangerous, with land mines floating around, with the possibility of those exploding at any time.

It's dire, and we're extremely concerned.

GEOFF BENNETT: Meantime, Ukrainian President Volodymyr Zelenskyy said today that he was shocked at what he said was the failure of the Red Cross and the United Nations to provide help after the dam collapse.

He said of your organization -- quote -- "They aren't here."

How do you respond to that?

EWAN WATSON: Well, I think the frustration is understandable.

And we can recognize that.

When you see the humanitarian needs in front of you, then it's only understandable.

What I would say is that our partners are working incredibly hard on the ground.

And we support them in many, many different ways, through technical support and other, to make sure that they are best placed to do that evacuation work and make people make sure that people have some drinking water, and some basic necessities.

Where our role is going to become stronger with time is in terms of tackling the longer-term needs of this, because, of course, what you have got is an area now that typically was used for agriculture.

And now that land is no longer available for agriculture, between the flooding and the land mines.

And, therefore, what are people going to do in terms of making a livelihood?

That's a desperate concern.

The other one is just the availability in the longer term of drinking water.

These are two massive concerns, yes, for today, but also for the longer term.

And that's where we expect to work very closely with our partner on the ground helping the communities.

GEOFF BENNETT: When President Zelenskyy says, we have had no response, I am shocked they aren't here, to what then do you think he's referring?

EWAN WATSON: I mean, I don't want to comment further on what the president is saying here.

I think, from the humanitarian perspective, we have sought to respond across Ukraine since the intensity of this conflict broke in February last year.

I think what's important here is that, firstly, we really echo what is an important point of law here, which is that a dam, just like a nuclear facility, must be protected.

It should not be attacked during warfare.

That's against the law.

And the problem when there is an attack like this is that it unleashes these dangerous forces, water that moves land mines in different directions, that then triggers all sorts of additional dangers to a population already in grave danger.

So we have been working since day one of this international armed conflict to respond to the different needs across the country.

And we will -- we will continue to do so.

GEOFF BENNETT: To your point, this is the most significant damage to civilian infrastructure since the start of this war.

It has far-reaching and grave consequences.

How does this compound what people across Southern Ukraine are already experiencing with this brutal war?

EWAN WATSON: Yes, I mean, I think, if you take a city like Kherson, which, of course, has been and remains at the epicenter of this conflict, that's a city that has been taken and retaken.

It has been -- it has been really at the center of a front line that has seen vicious fighting, where people have had to flee, possibly felt safe enough to come back, and now again wondering where the next foothold of safety lies.

So, that can -- you can just see that happening in all sorts of different communities in this region.

And if you look further east, of course, there's been conflict raging there since 2014.

So, for many communities in these areas, fighting is nothing new.

They have had to live in the middle of it.

They have had to live in the middle of shifting front lines, working out how to find daily bread each day.

It's a devastating situation, and it's not getting better.

It's not getting better.

It's getting worse.

GEOFF BENNETT: Ewan Watson, head of communications with the International Committee of the Red Cross, thank you for your time.

EWAN WATSON: Thank you.

AMNA NAWAZ: Today was one of the busiest days of the Republican presidential campaign so far, as Mike Pence and Doug Burgum joined the race.

We will look at both of the new candidates, starting with the former vice president.

As Laura Barron-Lopez reports, during his kickoff in Iowa, Pence drew a sharp contrast with his former running mate.

MIKE PENCE (R), Presidential Candidate: I stand before you today as a candidate for president to say to the Republican Party, the Republican Party must be the party of the Constitution of the United States.

(CHEERING AND APPLAUSE) LAURA BARRON-LOPEZ: The right-wing radio host turned politician serving six terms in Congress and four years as Indiana governor before joining the Trump White House now hopes to take the top job himself.

MIKE PENCE: Anyone who puts themselves over the Constitution should never be president of the United States.

(APPLAUSE) MIKE PENCE: And anyone who asks someone else to put them over the Constitution should never be president of the United States again.

(CHEERING AND APPLAUSE) MAN: If you would bow your head and your hearts.

LAURA BARRON-LOPEZ: One of the most outwardly evangelical Christians in government, Pence's faith and conservatism have defined his career.

Elected governor of the Hoosier State in 2012, Pence enacted a staunchly anti-LGBTQ and anti-abortion agenda.

In 2015, Pence supported a bill that allowed businesses to discriminate against LGBTQ customers, under religious objections, a law he quickly amended after facing national backlash.

In the lead-up to his presidential bid, Pence has called for a nationwide abortion ban and an end to the commonly used abortion medication pill mifepristone.

MIKE PENCE: I'd like to see this medication off the market to protect the unborn.

LAURA BARRON-LOPEZ: As Trump's vice president, Pence stood by Trump's side throughout his time in office, until January 6, 2021.

Trump repeatedly pressured Pence to reject certification of the 2020 presidential election and overturn the will of voters.

DONALD TRUMP, Former President of the United States: If Mike Pence does the right thing, we win the election.

LAURA BARRON-LOPEZ: A mob incited by Trump descended on the Capitol, searching for Pence.

RIOTERS: Hang Mike Pence!

Hang Mike Pence!

LAURA BARRON-LOPEZ: Pence refused.

MIKE PENCE: To those who wreaked havoc in our Capitol today, you did not win.

LAURA BARRON-LOPEZ: In the years since, Pence has seesawed between criticizing Trump for his role in the January 6 attacks... MIKE PENCE: When he returned in the months later to the rhetoric he was using before January 6, arguing that I had the right to overturn the election, I just decided it would best that we went our separate ways.

And we have.

LAURA BARRON-LOPEZ: ... but defended him on other matters.

MIKE PENCE: This is nothing short of a -- of a political prosecution being effected by a Manhattan DA who literally campaigned on bringing charges against one particular American.

While potential legal troubles still loom for Trump, including possible obstruction charges for retaining classified documents at Mar-a-Lago, Pence was recently cleared by the Justice Department, which closed its investigation into the discovery of classified documents at his Indiana home.

It's not clear if Pence will break through in a crowded primary, with his former boss leading the pack.

DARYL CHARLSON, Iowa Voter: I think Pence has a really, really great heart.

I think he's very intelligent.

The whole pool is probably one of the best pools I have seen for candidates ever.

I mean, it's just really crazy.

LAURA BARRON-LOPEZ: Pence will join CNN for a prime-time town hall this evening at Grand View University in Des Moines.

He's scheduled to travel to New Hampshire on Friday.

For the "PBS NewsHour," I'm Laura Barron-Lopez.

AMNA NAWAZ: And 400 miles away, in Fargo, North Dakota, Governor Doug Burgum also launched his campaign.

Lisa Desjardins reports on his record.

GOV.

DOUG BURGUM (R-ND), Presidential Candidate: Frankly, big cities can use more ideas and more values from small towns right now.

(CHEERING AND APPLAUSE) LISA DESJARDINS: North Dakota Governor Doug Burgum's presidential pitch is about his roots, far from Washington.

GOV.

DOUG BURGUM: Our whole town was about taking care of each other, about helping those in need, about neighbor helping neighbor.

Every small town in America is like that.

LISA DESJARDINS: In the 1980s, he took a chance, mortgaging his family grain farm to launch Great Plains Software.

That gamble paid off.

He sold the company in the 1990s to Microsoft for $1.1 billion.

MAN: Republican Doug Burgum.

LISA DESJARDINS: In 2016, he tried a new career, entering the governor's race with no political experience.

He easily beat an establishment candidate and won reelection four years later.

Energy policy, including drilling, is a focus for Burgum.

He's accused the Biden administration of waging a war on domestic fossil fuel production.

GOV.

DOUG BURGUM: It is a very simple thing.

If we want to have a global stable world and a strong U.S. economy, then we need to produce energy for ourselves and for our allies.

And we are not doing that.

LISA DESJARDINS: As for his GOP rivals... GOV.

RON DESANTIS (R-FL), Presidential Candidate: Florida is where woke goes to die!

(CHEERING AND APPLAUSE) GOV.

DOUG BURGUM: Woke is what you did at 5:00 a.m. to start the day.

LISA DESJARDINS: ... Burgum is attempting a nuanced contrast on social issues, saying the economy deserves more attention.

But he is socially conservative, recently signing a state law banning abortion at six weeks of pregnancy.

And the Human Rights Campaign says North Dakota is on track to pass more anti-LGBTQ legislation this year than any other state.

That includes a ban on gender-affirming health care for trans youth.

GOV.

DOUG BURGUM: We understand families and parents that are affected by it.

You know, it's a complex emotional issue.

LISA DESJARDINS: On immigration, Burgum recently directed more North Dakota National Guard troops to the Southern border.

But candidate Burgum is now looking east, with plans to talk to voters in Iowa and New Hampshire.

For the "PBS NewsHour," I'm Lisa Desjardins.

AMNA NAWAZ: So, with Burgum and Pence officially in, the Republican field grew by three this week.

Former New Jersey Governor Chris Christie kicked off his campaign last night in New Hampshire, and he's already set himself apart as the most vocal Trump critic in the race.

FMR.

GOV.

CHRIS CHRISTIE (R-NJ), Presidential Candidate: The person I am talking about who is obsessed with the mirror, who never admits a mistake, who never admits a fault, and who always finds someone else and something else to blame for whatever goes wrong, but finds every reason to take credit for anything that goes right, is Donald Trump.

AMNA NAWAZ: With nine candidates now on the stump, we take stock of the race with Whit Ayres.

He is a Republican strategist and the president of North Star Opinion Research.

He's previously consulted Republican candidates, including Senators Marco Rubio and Lindsey Graham and Florida Governor Ron DeSantis.

Whit, good to see you.

thanks for being here.

WHIT AYRES, President, North Star Opinion Research: Good to be here.

Thank you.

AMNA NAWAZ: So when you take a look at this field -- let's take a look at these nine candidates right now who are vying for the Republican nomination -- is this where you expected the Republican field to be right now?

What do you see when you look at this?

WHIT AYRES: We saw that a lot of people were interested and would want to try their hand.

And a lot of people are worried that it's going to be like 2016 all over again, where you divide the non-Trump vote and allowed Trump to win majority -- or a majority of the delegates by getting a plurality of the vote.

But the key is not the number of people who start.

The key is the number of people who stay in long after they could possibly win the nomination.

The model is the Democrats in 2020.

When Joe Biden won South Carolina, within ours, many of the candidates dropped out and endorsed him.

On the other hand, in 2016, candidates like John Kasich stayed in long after he had any realistic chance.

He got 7 percent of the vote in Virginia.

Marco Rubio would have won Virginia and beaten Donald Trump if John Kasich had not been in the race.

So the key to watch for Republicans is how many stay in when they have got no chance.

AMNA NAWAZ: And you say stay in, past those early states, past South Carolina in this case?

WHIT AYRES: Yes, yes, stay in past South Carolina.

Just like the Democrats did with Joe Biden - - after South Carolina, they got out and endorsed him.

AMNA NAWAZ: I want to ask you about some of the specific candidates, especially the ones that joined the race this week.

The line that Mike Pence has to walk here, running against the man alongside whom he served for four years, whose supporters said they wanted to kill him on January 6, what do you make of how he's messaging along those lines right now?

WHIT AYRES: Mike Pence, who, by all accounts, is a very good man, is caught between a rock and a hard place.

He's not Trumpy enough for the Trumpies, and he's too Trumpy for the non-Trumpies.

So he's got a very difficult line to walk.

We will see if he can make that work.

But it's a tough, tough line.

AMNA NAWAZ: What do you make of how Chris Christie has set himself apart now?

Does his ramping up his attacks against Donald Trump, does that force other candidates to meet him where he is?

WHIT AYRES: No.

Chris Christie is very talented and very good at making an argument, very powerful at making an attack on his opponents.

But the Republican Party is split into three factions.

There's a never-Trump faction that's only about 10 percent.

There's an always-Trump faction of about 35 percent.

Those people are always going to be with Trump regardless of the opponent.

The majority of the party, about 55 percent, are maybe-Trump voters.

They have supported him twice.

They would vote for him again against Joe Biden, but they're worried about his electability.

They're worried he carries too much baggage, and they're looking for alternatives.

Chris Christie's message, arguing that Donald Trump is unfit for office, appeals to the never-Trumpers.

But he's going to tap out at about 10 percent.

Saying that Donald Trump was unfit for office is an insult to the maybe-Trump voters who supported him twice.

So he's got no chance with those people.

The other candidates are trying to consolidate the maybe-Trump portion of the party.

AMNA NAWAZ: So I want to play for you one voter we heard from in New Hampshire who speaks exactly to that.

It's a woman named Nancy Malonson.

And here's what she had to say.

NANCY MALONSON, New Hampshire Voter: Trump is amazing, but a lot of people don't like him.

So do we want to be in that situation where they really -- it's just really -- it's sad that our country has so much hatred towards that man.

So maybe we do need new blood.

AMNA NAWAZ: So there are a number of candidates polling in the low single digits right now.

If they want to appeal to people like Nancy Malonson, what's the message that you think those other candidates have to carry forward?

WHIT AYRES: They have to look and act like a successful president of the United States.

They have got to be able to capture public attention.

They have got to be able to capture any kind of excitement that they possibly can.

And who knows.

There's a lot of talent in this field.

And somebody may catch fire, but they're going to have to catch fire in a big way in order to surpass the lead the Donald Trump currently has.

AMNA NAWAZ: In the 40 seconds or so we have left, who do you see among some of those other candidates, Nikki Haley, Tim Scott, Asa Hutchinson, who could break through, particularly in these early states... WHIT AYRES: Yes.

AMNA NAWAZ: ... of Iowa, New Hampshire, Nevada, and South Carolina?

WHIT AYRES: I think any of them could.

The history is replete with candidates who started off as asterisks in the race and then ended up winning Iowa or coming in a close second and then doing really well in New Hampshire.

So it's all a matter of the candidate, kind of campaigns that they run and whether they can catch fire at the right time.

AMNA NAWAZ: You will be tracking it all.

So we will.

Whit Ayres, always good to see you.

Thank you so much.

WHIT AYRES: It's a pleasure.

Thank you.

AMNA NAWAZ: A new study reveals just how crucial the first 30 seconds of a police encounter can be, in particular for black drivers.

Since the high-profile police killings of Philando Castile, Daunte Wright, and Tyre Nichols, all of which began as traffic stops, calls for de-escalation by officers have been growing.

The study in the Proceedings of the National Academy of Sciences analyzed body camera footage in 577 traffic stops of black drivers in one midsize American city over a month.

It found that the first 45 words spoken by the police officer could determine how that encounter ended.

To help us understand what this can mean for the future of policing, I'm joined by Tracey Meares, professor of law and founding director of the Justice Collaboratory at Yale Law School.

She was also among those who reviewed this particular study.

Tracey Meares, welcome back.

Thanks for joining us.

TRACEY MEARES, Justice Collaboratory Founding Director, Yale Law School: Happy to be here, Amna.

Good to see you.

AMNA NAWAZ: So, the study found that if the police officer began the encounter by issuing a command or not giving a reason for the stop, it was three times more likely that the interaction would escalate, that the driver could be searched or handcuffed or arrested, versus if the police officer began with a greeting.

Did that finding surprise you?

TRACEY MEARES: It didn't surprise me.

It's very consistent with much of the work that I have done over the past decade or so.

What I do think is incredibly notable about this particular research study was the precision with which they were able to measure the time to predict an escalation and the specific words.

AMNA NAWAZ: And just to be specific here, what are we talking about in that early interaction?

It's the difference between an officer saying, hello, sir, how are you, versus, let me see your license and registration?

What are we talking about?

TRACEY MEARES: What we're talking about is the extent to which, when an officer stops a person for a traffic violation, typically, very low-level violations, whether that officer actually takes an opportunity to tell the driver why the driver was actually stopped.

And what the research shows is, in the situations in which that doesn't happen -- or let me back up.

In situations in which there is an escalation, it is 2.5 times more likely that the officer didn't explain the reason for the stop.

That's what the research found.

AMNA NAWAZ: So, nearly 98 percent of the drivers who experienced one of those escalated outcomes was black.

What does that tell you about implicit bias and racism that persists in our policing today?

TRACEY MEARES: I think one of the things that's incredibly interesting about this study -- and it's worth folks taking a chance to read it - - is, the reason why the researchers focused on black drivers, 577 of them, as you noted, was that, in one out of six of those stops, those stops ended in an escalation, an arrest, a search, handcuffing or the like.

They also did assess white drivers, 267 incidents during that same time period where white drivers were stopped, but only four of those resulted in an escalation.

So, we have got to kinds of disparities here.

First, many, many more drivers, black drivers, were stopped in the first instance for traffic violations.

And, second, a much higher percentage of black drivers experienced escalations than did white drivers.

So they focused on the black driver.

AMNA NAWAZ: So, Tracey, how do we solve for this from policing or a training standpoint?

Because we have heard a lot about implicit bias training.

These officers were all wearing body cameras.

TRACEY MEARES: Right.

AMNA NAWAZ: Presumably, they didn't think they were doing anything wrong.

TRACEY MEARES: Yes, it's fascinating.

I mean, the work that I have done on procedural justice suggests that it's very important to explain to people why you are stopped, because it makes people believe that they are -- or come to conclusions that their interaction is much more fair than when that situation doesn't happen.

So, one thing you can do is actually train officers to engage in that explanation.

However, many of those officers were very likely trained to do so.

So, it does bring a question, why, in the situations in which there was escalation, did they either decide or subconsciously fail to explain what they're doing?

I think that cause -- calls for much deeper research into the exactly the kind of bias that you're talking about.

AMNA NAWAZ: Tracey, as you know, a lot of the burden right now seems to rest with those black drivers: How do I keep myself safe?

How do I comply?

How do we shift the burden to the person who has power in that situation, to the police officer?

TRACEY MEARES: I think one of the ways we shift the burden to the police officer is by limiting the opportunities for the police officer to engage in this -- in this regulation to begin with.

Historically, police officers were the ones who were essentially traffic lights.

They stood in the middle of the streets and they directed traffic.

We now automate that.

And I think we have seen today that, with cameras and other things, we can do that kind of more automated regulation of traffic violations as well.

AMNA NAWAZ: That is Tracey Meares, professor of law and founding director of the Justice Collaboratory at Yale Law School, joining us tonight.

Tracey, thank you.

TRACEY MEARES: Thanks, Amna.

GEOFF BENNETT: In the aftermath of the MeToo movement, a new field has come to prominence in the film and theater industries, intimacy coordinators and directors.

This role puts a focus on consent and safety for actors and the production teams.

Jeffrey Brown has a look as part of our arts and culture series, Canvas.

JEFFREY BROWN: The touch of a face, clasping hands, an embrace, it's a different kind of choreography on set or stage, one of intimacy.

CLAIRE WARDEN, Director of Advanced Training, Intimacy Directors and Coordinators: Whoever hasn't been the outside eye will now be the outside eye.

JEFFREY BROWN: And a new kind of training.

MAN: Your actors are coming in knowing that they're doing the kiss.

They're falling onto the bed and then they're starting to... JEFFREY BROWN: Of what are called intimacy coordinators in TV and film and intimacy directors in theater.

JESSICA STEINROCK, CEO, Intimacy Directors and Coordinators: Intimacy coordinators and intimacy directors help make intimate scenes look real, when they're actually fake.

JEFFREY BROWN: Jessica Steinrock started her company IDC in 2019 to certify and bring more people into this growing field.

She herself has worked on Showtime's "Yellowjackets," Netflix's "Never Have I Ever," and Hulu's "Little Fires Everywhere."

JESSICA STEINROCK: We are actor advocates, we are liaisons for the sets and the crew, and we are also there as choreographers to help set movement and make sure that everybody's boundaries are respected in the creative process.

CLAIRE WARDEN: Creating choreography from up front.

JEFFREY BROWN: We watched a recent class in New York led by Claire Warden, an actor turned intimacy director and coordinator.

CLAIRE WARDEN: Two of you will be creating the physical storytelling.

JEFFREY BROWN: To teach some of the fundamentals of movement, but also how to watch carefully and talk through issues with actors and directors.

CLAIRE WARDEN: We're also physical storytellers.

So we are creating agreements of movement or choreography sometimes in order to keep the clarity about physical storytelling and the boundaries that have been agreed on by the actors telling that story consistent.

JEFFREY BROWN: So, Jessica, do you see this as a real sea change in Hollywood and theater?

JESSICA STEINROCK: Oh, 100 percent.

Physically having this new role dramatically alters the landscape of entertainment, creates space for conversation, where, before, there was less space.

JEFFREY BROWN: It's an industry in which everyone understands the meaning of the casting couch, and stories abound of actors being surprised, taken advantage of, traumatized.

Then-19-year-old Maria Schneider in 1973's "Last Tango in Paris" said she felt -- quote - - "a little raped" in a scene with Marlon Brando.

Director Bernardo Bertolucci would later admit he did not tell Schneider ahead of time how he wanted the scene to unfold.

Actress Sharon Stone has said she was told parts of her body would not be shown in a scene in 1992's "Basic Instinct," but later found out that wasn't the case.

CLAIRE WARDEN: For every story that the public get to hear, there are tens, hundreds of thousands of stories that we don't get to hear from similar people.

JEFFREY BROWN: This past January, the leads in 1968's "Romeo & Juliet," Olivia Hussey and Leonard Whiting, filed a lawsuit against Paramount for exploitation and using nude images of them, teenagers at the time, that they were told wouldn't be used in the film.

A California judge recently ruled the case could not go forward, citing First Amendment and technical barriers.

But a lawyer for the actors said they would file a new suit in federal court.

KRISTY GUEVARA-FLANAGAN, Director, "Body Parts": There's a lot of potential for danger and coercion.

JEFFREY BROWN: Kristy Guevara-Flanagan is a professor of film, TV and digital media at UCLA.

She directed "Body Parts," a documentary that depicts the history of sex on screen.

Directors, historians, and actors including Jane Fonda, Rosanna Arquette, and Rose McGowan, share their experiences in the industry.

KRISTY GUEVARA-FLANAGAN: There's so much power differential in Hollywood, I think.

Young women were feeling like they didn't know how to navigate this, that they were feeling pressure, and that they felt like they didn't have a lot of options.

JEFFREY BROWN: As far back as 1967, SAG-AFTRA, the union representing thousands of actors, developed the nudity rider, a legal agreement used to clarify parameters of filming an intimate scene.

As of 2020, these riders are now decided upon 48 hours in advance.

But Jessica Steinrock says things can still change in the intensity of the moment.

JESSICA STEINROCK: There's a lot of money involved, a lot of crunch time involved.

And when we have power dynamics, we also have opportunities for folks to lose their ability to give consent.

And so what the intimacy professional really does is help reconstruct the entertainment landscape so that everybody is really excited and feels consenting about what those actions are going to be on any given day.

JEFFREY BROWN: A recent turning point, HBO's 2018 "The Deuce," a drama series set amid the pornography industry in 1970s New York.

It took on a coordinator after actress Emily Meade spoke out about issues on set.

HBO then began to require coordinators on all productions with intimate scenes, helping to set a new standard throughout the industry.

KRISTY GUEVARA-FLANAGAN: The main thing that allowed for this was really the Time's Up and MeToo movement and the Harvey Weinstein scandal coming to light.

People were finally having to answer to these questions of like, what has been happening on their own sets?

Where have people not felt protected, and what can be done?

JEFFREY BROWN: Sarah Polley, who began acting as a child, has written of traumatic situations she was put in during filming, in her case not involving sex.

Now a director herself, that's influenced how she runs her sets.

We spoke recently about her Oscar-nominated film "Women Talking."

SARAH POLLEY, Director: I think, for so long now, it's been considered a badge of honor to tell war stories as a filmmaker about the way you manipulated people or betrayed people or told them something, when something else was actually happening, in order to get a great moment.

But I'm always curious, if those same filmmakers could remake their films and behave with a certain amount of decency and care, I wonder if they'd make even better films, even the good ones.

I wonder if they would have been better if people had felt safe.

We will never know.

JEFFREY BROWN: Speaking recently to actress Rachel McAdams about her new film, "Are You There God?

It's Me, Margaret," also asked about the new higher-profile role of intimacy coordinators.

RACHEL MCADAMS, Actress: I feel like the intimate scenes I have done that have gone -- have been most successful have been very well-choreographed.

I don't think it takes anything away.

I think it's totally additive.

And I'm really glad it's a part of the business now.

And I think it should always be there as an option.

ARIELLA SALINAS FIORE, Trainee, Intimacy Directors and Coordinators: Thinking of it in a technical sense.

I have been doing the emotional work.

JEFFREY BROWN: Back at the workshop, student Ariella Salinas Fiore says her desire to do this work was shaped by her experience as an actor, director and producer.

ARIELLA SALINAS FIORE: I did come from this mentality of, no, you just say yes.

You just do the work.

You don't need to do -- be difficult, and me myself realizing, well, maybe there is a better way.

JEFFREY BROWN: Shelby Terrell, another trainee, agrees.

SHELBY TERRELL, Trainee, Intimacy Directors and Coordinators: If we can practice these things in our daily lives, normalize it and create a culture of consent in our lives, in TV and film on set, it will just change the culture and change lives.

JEFFREY BROWN: Jessica Steinrock says she too hopes intimacy coordinators become the rule, not the exception.

JESSICA STEINROCK: We have animal wranglers and stunt coordinators.

If there's children on set, there's a specialist for that.

These scenes are so complicated and vulnerable, it's almost shocking that we haven't had specialized support in these scenes until now.

CLAIRE WARDEN: The climax has an explosion of breath.

JEFFREY BROWN: For the "PBS NewsHour," I'm Jeffrey Brown in New York.

AMNA NAWAZ: And we will be back shortly.

But, first, take a moment to hear from your local PBS station.

GEOFF BENNETT: It's a chance to offer your support, which helps keep programs like this one on the air.

AMNA NAWAZ: For those of you staying with us, we take a second look at a piece of history at risk.

Steam engines are fired by coal.

And the price of that fuel has skyrocketed in recent years.

In turn, that is jeopardizing the future of some of Britain's living and breathing museums.

From Southwestern England, special correspondent Malcolm Brabant reports.

MALCOLM BRABANT: They're burning through money at the Swanage Railway, as is every historic line in the land which gave birth to steam trains.

The locomotive hauling today's service is a 1940s vintage express, back to robust health after a $400,000 refit.

In total, there are 150 heritage railway lines in Britain, and all of them are facing the same problems.

This is the start of the new season, and they're all banking on good visitor numbers to help them survive.

GAVIN JOHNS, Chairman, Swanage Railway Trust: We have had to work very hard to address the impacts of the pandemic.

And coming out of that, we have still got major challenges ahead of us.

MALCOLM BRABANT: Leading the effort to keep this living museum on the right track is Gavin Johns, who has more than 30 years' experience with Britain's modern rail network.

GAVIN JOHNS: We have got two challenges, one, rising costs and the impacts of those rising costs on our customers.

So, our own costs are going up significantly, most notably, coal.

MALCOLM BRABANT: Three years ago, the daily spend on coal was $670.

Today, it's $1,600.

GAVIN JOHNS: Coal is a major issue for us, because, before the war in Ukraine, we were sourcing our coal from Russia.

So we had -- very quickly had to work with our supplier to switch the source of the coal.

MALCOLM BRABANT: Can you ever go back to Russian coal?

GAVIN JOHNS: I think its very unlikely that we will go back to Russian coal supplies.

We have been working hard to find new sources.

And I think, for the time being, that we will stick with those sources.

MALCOLM BRABANT: Johns says that ethical considerations, and not just sanctions, dictate the railway's stance.

Although costs have more than doubled, it'll try to absorb the hit and not raise ticket prices, because visitors are also struggling financially.

The hope is that more passengers like Matt Collins will turn up for a steam fix.

MATT COLLINS, Hotelier: Marvel at what steam engines were at the time.

Basically, it's controlled explosions, a real lesson in engineering.

And it's really evocative, the smells, the sights and the sounds, as you travel on these trains.

And it just gives you an insight into what the Victorians did for us.

MALCOLM BRABANT: While steam engines pump out carbon dioxide, along with water vapor, the biggest environmental impact of the locomotive age was to encourage air pollution by other heavy industries.

Today, the influence of heritage lines on climate change is negligible.

The railways insist they're using cleaner coal where possible and are trying to reduce their carbon footprint elsewhere.

In Swanage, aficionados like Suzanne Wiseman have no qualms about keeping steam alive.

SUZANNE WISEMAN, Passenger: It means a lot to me, because I was brought up in the steam railway era.

And we were just saying, actually, I remember standing on the railway bridges just watching them go under, and the driver used to always give us a peep and wave.

And it's just nice.

It's keeping a bit of the British heritage going.

I think people all over the world love us for our history, and this is a big part of it.

MALCOLM BRABANT: This heritage line benefits from being in a region that's popular with vacationers and day trippers.

Nevertheless, it's laid off a handful of permanent staff.

Other railways have been harder-hit and have been forced to make more drastic cuts.

STEVE OATES, Chief Executive, Heritage Railway Association: Railways have been using timber, steel for all the repairs, track renewals, locomotive and carriage renewals and so on.

So the cost of these sorts of commodities have all shot up.

So, yes, there are some railways at risk, absolutely.

MALCOLM BRABANT: As chief executive of the Heritage Railway Association, Steve Oates has an overview of the sector's myriad problems.

So, how would you categorize it?

STEVE OATES: It's tough.

It's looking tricky, because the economic challenges that everybody is facing and the cost of living crisis, which is affecting potential visitors, it's almost like a double or triple whammy.

MALCOLM BRABANT: Third-class travel is a concept that many British people can now grasp, as their living standards decline and they cut back on luxuries.

But Oates hopes that the allure of steam will prevail.

STEVE OATES: I think people will reluctantly put hands in pockets, as they did during COVID.

But it is a risk.

There's no question about it that there is a risk.

And railways do need to be really careful about this.

MALCOLM BRABANT: Even the popular Bluebell line, 130 miles east of Swanage, is not immune.

It relies on volunteers like Patricia Beale, who spent a lifetime working on modern railways.

PATRICIA BEALE (Station Foreman): It's something that gets in your blood.

I mean, I love railways and steam engines, the smell and just the general ambiance.

Steam engines are living creatures, or they appear to be living creatures.

They breathe.

MALCOLM BRABANT: Love and tender care have helped this Terrier class locomotive survive its contemporaries.

Now 150 years old, this is the little engine that could help pull the Bluebell over the economic mountain.

The railway's chairman is Paul Churchman.

PAUL CHURCHMAN, Chairman, Bluebell Railway: Morning.

Everything OK?

MAN: Yes.

PAUL CHURCHMAN: Ready for a busy day?

MAN: Hopefully, yes.

PAUL CHURCHMAN: Good.

MAN: Weather is not looking too bad at the minute.

PAUL CHURCHMAN: No.

Hopefully, we should have enough people in today.

We're working very hard, but we have to be realistic in that it's going to be very challenging.

MALCOLM BRABANT: The Bluebells' costs have also doubled because of the war in Ukraine, even though this coal doesn't come from Russia.

PAUL CHURCHMAN: Last year wasn't that good because of the rising costs and the softening of revenue.

We expect to post a loss for last year.

This year, we probably will post a loss again, but we are taking actions to get our business to break even for 2020.

MALCOLM BRABANT: The Bluebell and other lines can no longer rely on pure nostalgia as a crowd-puller.

They need to wrench young people away from the screens of their devices.

Nineteen-year-old Luke Hopgood, no longer volunteers, but keeps coming back.

LUKE HOPGOOD, Former Bluebell Volunteer: There's just old-fashioned stations, and it's just very traditional.

And there's just a very authentic feel about it.

MALCOLM BRABANT: This station is a favorite with film producers.

It featured in the "Downton Abbey" series, but the Bluebell can't rest on its laurels.

PAUL CHURCHMAN: People don't want to just come for a train ride anymore.

It needs to be so much more than that.

You need to have the added value to the day out in the visitor experience.

GAVIN JOHNS: We have got a steam gala coming up in a few weeks with some great engines coming, which we know will attract enthusiasts.

MALCOLM BRABANT: The Swanage line was axed from the British network in 1972.

Gavin Johns has no intention of letting it die a second time.

GAVIN JOHNS: We have got a great set of volunteers who help the railway out.

We have got a great set of staff that work really hard to keep things moving.

And I think that, with our special events and with the determination, and we have got a really good chance of surviving.

MALCOLM BRABANT: This summer, in a new initiative, this heritage diesel train will connect to mainline services for the first time in 50 years.

The message from all 150 historic railways is the same.

PAUL CHURCHMAN: Come here.

Spend your money.

(LAUGHTER) PAUL CHURCHMAN: Help us survive.

Enjoy the experience we have.

It is unique.

MALCOLM BRABANT: Can they make it?

They think they can.

They think they can.

For the "PBS NewsHour," I'm Malcolm Brabant in Southern England.

GEOFF BENNETT: The legacy of novelist Willa Cather is being honored on Capitol Hill today.

A bronze statue of the Pulitzer Prize-winning author was unveiled in the U.S. Capitol's Statuary Hall.

Cather is best known for "My Antonia" and other novels about frontier life and the immigrant experience published in the early 1900s.

The sculpture represents Nebraska, where Cather spent most of her life.

It's also the first time the work of an African American artist will be displayed in Statuary Hall.

The sculptor, Omaha artist Littleton Alston.

And you can watch our profile of Alston, where he describes the inspiration for his work.

That's on our Web site, PBS.org/NewsHour.

AMNA NAWAZ: Also online: It's not your imagination.

More places are asking for tips these days, part of a post-pandemic trend.

We asked two experts for their take.

LIZZIE POST, "Emily Post's Etiquette": The prevalence of those tips greens when we emerged from all of our lockdowns and everything really did put a lot of pressure, and I think created a little bit of confusion for a lot of Americans.

You were starting to see tip screens in places where you were not typically prompted for it.

And I think being -- having to actually go through the action of saying, no, I do not want to leave a tip, that is where we started hearing a lot of people getting uncomfortable.

MICHAEL LYNN, Cornell University: When you talk to businesses and employees of businesses that have adopted these new digital technologies, they will tell you that their tips have increased.

But there is no good scientific data on this, in part because, although once you adopt technologies, you have good records of tips after the fact, but you don't have good records from before to compare it with.

But the anecdotal data we have, I think, is reasonably persuasive, and it suggests that, yes, people are tipping more because of the increased request for tips.

AMNA NAWAZ: And you can watch that full conversation for more about when and how much you should tip on our Web site.

GEOFF BENNETT: And that is the "NewsHour" for tonight.

I'm Geoff Bennett.

AMNA NAWAZ: And I'm Amna Nawaz.

On behalf of the entire "NewsHour" team, thank you for joining us.