AMNA NAWAZ: With celebrations for the nation's 250th anniversary well under way, the mood of the country and its citizens can best be summed up as complicated.

That's according to a new PBS News/NPR/Marist poll.

Most Americans say the nation has drifted from its founding ideals, and a growing number say the divisions have become so severe that violence may be necessary to set the country back on the right path.

Liz Landers has more insights from the poll and its respondents.

LIZ LANDERS: Flags, fireworks and fanfare.

Beneath the pageantry of the country's 250th birthday, some feel a sense of national pride.

GERALD JAKUBOSKY, Florida Resident: I have been fortunate to travel and work with a lot of people from all around the world.

This is a good place.

I mean, with all its faults, there's not much like it in the world.

LIZ LANDERS: Gerald Jakubosky remembers America's bicentennial 50 years ago, which he says felt like a national party.

He says something is different this year.

GERALD JAKUBOSKY: This time it's, unfortunately, not as joyful as it could have been.

LIZ LANDERS: At this milestone moment, two-thirds of respondents in the latest PBS News/NPR/Marist poll said they are proud to be American.

One-third are not.

Those feelings are largely defined by political alignment, and the partisan gap is enormous; 93 percent of Republicans say they are proud.

Just 45 percent of Democrats and 61 percent of independents say the same.

VERONICA VALDIVIA-VERA, Michigan Resident: I am not proud.

It's embarrassing what is happening in this country.

LIZ LANDERS: Veronica Valdivia-Vera is a naturalized citizen and a political independent.

She says the Trump administration's anti-immigration agenda has her worried.

VERONICA VALDIVIA-VERA: I was born in Mexico, so it fills me with sadness to see what is happening to immigrants, other fellow immigrants, and how we're being targeted because OF the color of skin.

LIZ LANDERS: Nearly half of Americans say the country has moved far away from the principles and ideas on which it was founded.

Just 16 percent say it still represents the nation's founding beliefs.

MARK HOCKING, Indiana Resident: I think it's come a long way from the beginning.

It was nowhere close to perfect at the beginning of this country.

And I think we have come a long way.

LIZ LANDERS: Mark Hocking is a political independent from Indiana.

He's proud, he says, but clear-eyed about how far the country still has to go.

LEE MIRINGOFF, Director, Marist Institute for Public Opinion: There are doubts about where we are and where we're headed.

LIZ LANDERS: Lee Miringoff is the director of the Marist institute for Public Opinion.

LEE MIRINGOFF: I don't think it's really surprising, as much as it can be still considered shocking, that after 250 years of this grand experiment in democracy, folks are having serious doubts and wondering how far we have strayed from our principles.

LIZ LANDERS: Those early founding statements, that all men are created equal, that the pursuit of happiness is a central right, continue to face new tests in the 21st century.

BEVERLY GAGE, Yale University: There are lots of people that are really questioning in this moment whether those things are true anymore.

LIZ LANDERS: Beverly Gage is a historian at Yale University and author of "This Land is Your Land: A Road Trip Through U.S.

History."

BEVERLY GAGE: There have always been in the United States deep concerns about whether the country would hold together, whether we're just this big mishmash of different kinds of people with different experiences and different beliefs, or whether there's something that really unites the country.

I think we're seeing a particularly acute sense of concern over these questions now.

LIZ LANDERS: But what does it mean to be an American?

In the new poll, freedom or liberty was the most common response.

More than a third of respondents said so.

Other common answers included patriotism, constitutional rights and diversity.

MARK HOCKING: To be an American, I think just the opportunity, that we -- anybody can do anything based on ability, but also based on circumstance.

LIZ LANDERS: Despite clear differences in the view of American identity, there was some overwhelming agreement.

More than eight in 10 respondents said that the issues that divide the country pose a serious threat to the future of democracy.

LEE MIRINGOFF: There's very few institutions who have not developed recent scars from just the kinds of sentiment that people are seeing when things are not improving.

LIZ LANDERS: As Americans see stagnation in the direction of the country, there is also an uptick in acceptance of political violence; 37 percent of Americans believe their fellow citizens may need to resort to violence to get the nation back on track.

That's a seven-point increase since October.

BEVERLY GAGE: It's not a great sign for our democracy.

LIZ LANDERS: Gage says the current sentiment is not without historical precedent.

Violence has been a part of the American story from the very beginning.

But she says what distinguishes this moment is what makes it most alarming.

BEVERLY GAGE: The two things that I think are really distinct about our moment are, one, the seeming popularity or resignation to the idea that violence might become necessary, and, secondly, the technology, the weaponry we have today, the widespread nature of gun ownership and the ways that violence can be turned into mass violence much more easily than it could in the past.

LIZ LANDERS: And the poll finds the rising belief is driven most sharply by young Americans.

More than half, 58 percent, of respondents under age 30 say violence may be necessary.

That's a 17-point jump since October.

JACK BORCHERS, Illinois Resident: I think it's something that I can definitely see people doing.

LIZ LANDERS: Twenty-one-year-old college student Jack Borchers is a Democrat.

While he doesn't think he'd take up arms, he understands why other young people might.

JACK BORCHERS: I personally do not want to see violence.

I think that we need to resolve our issues about violence, but I think that it's going towards that path.

It's kind of an unavoidable.

One half of the aisle doesn't seem to want to play by the rules, so it may be time for both sides to kind of agree that the rules need to be broken.

LIZ LANDERS: Despite the grim outlook on creeping political violence, there is room for some optimism.

A majority of Americans, 53 percent, say that America's best days are ahead.

GERALD JAKUBOSKY: Administrations change.

Maybe this one will go down as you know, maybe that wasn't so great.

But there's always another one.

It can be better.

JACK BORCHERS: I hope that those ideals and ideas that they came up with 250 years ago will still exist 50 years from now at the nation's 300th birthday.

LIZ LANDERS: Two hundred and fifty years in, the poll finds a country with a common vocabulary, freedom, opportunity, the promise of something better yet to come.

BEVERLY GAGE: Moments like the 250th, I think also help people step back, take a little perspective on the moment that we're in, and, by the measures of history, maybe come to the conclusion that, while there are certainly deep problems today, maybe all is not so doom and gloom.

LIZ LANDERS: What still divides Americans today is whether they believe those founding ideals and the promises of a new nation are still being kept.

For the "PBS News Hour," I'm Liz Landers.