AMNA NAWAZ: Achieving the so-called American dream has been a national ethos for generations.

But what does it mean today and how attainable is it?

Judy Woodruff has our look.

It's part of her series Crossroads: America at 250.

MAN: Will my candidates for citizenship please raise your right hands and repeat after me?

JUDY WOODRUFF: On a recent afternoon in downtown Washington, D.C., 25 immigrants from 14 countries took the oath of allegiance and posed with certificates of naturalization, officially becoming U.S.

citizens.

(APPLAUSE) JUDY WOODRUFF: The ceremony took place at the Milken Center for Advancing the American Dream, which celebrates the ideal that has drawn so many to this country.

DAVID TRULIO, President, Milken Center for Advancing the American Dream: This is a place built to strengthen freedom, opportunity, and hope, and to serve as a source of inspiration for anyone with a dream and the drive to achieve it.

JUDY WOODRUFF: David Trulio is the center's president.

DAVID TRULIO: In America, anything is possible, and that is at the core of the American dream.

JUDY WOODRUFF: On the walls here, personal success stories offer proof, as do the photos and notes visitors add to the tree sculpture in the center's main hall.

The tree is a testament to an idea with roots in the Great Depression.

DAVID LEONHARDT, Editorial Director, The New York Times: In 1931, a historian named James Truslow Adam wrote a book called "Epic of America," in which he coined this term the American dream, and he said it defines a happier, richer, better life for all of our people.

JUDY WOODRUFF: New York Times editorial director David Leonhardt wrote "Ours Was the Shining Future: The Story of the American Dream."

DAVID LEONHARDT: It's the idea that parents can expect that their children will have better lives than they did, and that their grandchildren will have even better lives than their children do.

JUDY WOODRUFF: During the post-World War II economic boom, working Americans had widespread access to affordable homes, college educations, and jobs that could support a stable middle class lifestyle.

DAVID LEONHARDT: Ninety-two percent of children born in 1940 grew up to earn more, adjusting for inflation, than their parents did.

That's remarkable.

That is a better, richer, happier life.

JUDY WOODRUFF: But the American dream was not equally accessible to everyone, prompting Dr.

Martin Luther King's famous "I Have a Dream" speech in 1963.

GEORGE CARLIN, Comedian: The table is tilted, folks.

JUDY WOODRUFF: Over the years, the American dream has had its skeptics, not just the marginalized.

GEORGE CARLIN: It's called the American dream because you have to be asleep to believe it.

JUDY WOODRUFF: Today, fewer than half of Americans say they believe everyone can achieve it.

Leonhardt thinks that pessimism is driven by stagnant wages and less economic mobility.

DAVID LEONHARDT: For children born in 1980, people who are now in their mid-40s, the odds of outearning your parents are only 50 percent.

It's more like a coin flip whether you're going to do better than your parents.

ART WILLIAMS, Retired: This is my mom and dad before he was sent overseas.

JUDY WOODRUFF: Art Williams was born and raised in Pennsylvania's Pocono Mountains, the son of a barber and a beautician.

ART WILLIAMS: My dad was a World War II vet.

I was a Baby Boomer.

I was born in 1947.

We grew up in a stable family.

ROXANNE WILLIAMS, Retired: This is a picture of me when I was little with my dog Frosty.

JUDY WOODRUFF: Art's wife, 74-year-old Roxanne (ph), grew up 70 miles away in Bethlehem.

Neither of her parents graduated from high school.

Still, she says: ROXANNE WILLIAMS: We were all comfortable.

My dad worked at the steel for over 40 years.

He worked in the blast furnace.

JUDY WOODRUFF: Bethlehem Steel's blast furnaces still tower over the city.

They're now rusted and dormant.

But, for years, Roxanne's father and thousands of others had well-paying union jobs here that helped them build a better life.

ROXANNE WILLIAMS: They had the American dream.

They owned their house.

They had a family.

The prospects were good.

JUDY WOODRUFF: Roxanne and Art built their own house near Bethlehem 50 years ago.

Art taught high school accounting for more than three decades to support Roxanne and their two daughters.

ART WILLIAMS: I think we have achieved probably more than my parents.

ROXANNE WILLIAMS: We never really wanted for anything.

And we traveled.

ART WILLIAMS: Fortunately, we were able to send both of our daughters to college, which we paid for.

JUDY WOODRUFF: Since Art's retirement 22 years ago, the Williams have lived on his pension.

ART WILLIAMS: That, with Social Security, that has moved us up a bracket, shall we say?

ROXANNE WILLIAMS: I just think we're where we're supposed to be and enjoying life.

JUDY WOODRUFF: The Williams 44-year-old daughter, Vanessa, and her husband, Dan, who is 47, live nearby with their daughter, Cora (ph).

Vanessa and Dan are both college graduates.

Neither is currently working.

DAN, Currently Unemployed: I have lost my job a number of times due to company financial decisions and whatnot.

VANESSA, Currently Unemployed: I have been right-sized.

I have been let go.

I have left on my own two feet a couple times, but most of the time, when we have changed jobs, unfortunately, it has not been our choice.

DAN: Right.

VANESSA: It is because there was a cutback or something like that.

JUDY WOODRUFF: The two of you have a college education.

You're well-educated people, and these kinds of things happen.

What do you think it says about our country, about our American way of life?

DAN: Loyalty has dropped.

The sentence I get is that the country doesn't care whether or not any of us succeeds.

DAVID LEONHARDT: I think there is less of a sense of we're all in this together than there used to be.

JUDY WOODRUFF: Leonhardt says that's a shift from the 1950s and '60s, for example.

DAVID LEONHARDT: When you go back and you look at the decades where we did have broadly rising prosperity, you really see this incredible sense of patriotism and community values from our corporate leaders.

JUDY WOODRUFF: It's one reason Vanessa, a communication strategist, and Dan, an engineer, say they feel the American dream isn't what it used to be.

DAN: Hard work should be enough, and I don't think it is.

VANESSA: I did everything that I was told by my parents and by society correctly, only to be met up with the recession and the housing crisis.

It's been bumpy.

JUDY WOODRUFF: Vanessa's 38-year-old sister, Brina, and her husband, Matt, live in York, Pennsylvania.

BRINA JONES, Co-Owner, Sips Cafe: I think, from the outside, people would look at us and think that we have realized the American dream.

We built this home that you are sitting in.

We have -- we might not have 2.5 kids, but we have two dogs and the fence and that type of ideal.

And I think partially we have.

JUDY WOODRUFF: Brina and Matt left more traditional careers to become entrepreneurs and now own two cafes called Sips.

Do you think you have done better than your parents?

BRINA JONES: I think we have done different than my parents.

I have been building what I guess would be my own American dream.

You might just have to do offline payments, Katie.

JUDY WOODRUFF: Building a business is risky, but they say the future looks bright.

MATT JONES, Co-Owner, Sips Cafe: Overall, I'm optimistic.

I'm pleased with what we have already accomplished.

I trust in us.

BRINA JONES: I think I feel pretty secure, and I think that we know that we're very lucky.

JUDY WOODRUFF: Sips has 20 employees, mostly young women.

WOMAN: Thirteen seventy-eight.

whenever we're ready.

JUDY WOODRUFF: Brina worries about the challenges they face.

BRINA JONES: It is hard for them, and they're not doing anything wrong.

They are just absolutely doing their best.

JUDY WOODRUFF: Twenty-Year-old Trinity Jackson (ph) works at Sips part-time.

She graduated from college over a year ago and is still looking for a full-time job while living at home.

TRINITY JACKSON, College Graduate: I struggle with feeling secure in my finances.

While I may not be where my parents were when they were my age, I'm still trying to do my best with what the current situation is.

JUDY WOODRUFF: That's despite feeling disillusioned by the American dream, like so many in her generation, amid rising living costs and a job market rocked by artificial intelligence.

TRINITY JACKSON: We're not trying to go for the same dream anymore.

The dream doesn't exist for us.

We can't own a home when we're 25.

We don't feel like we're in a place to bring children into the world if we can't pay our own student loans and pay off our own cars.

For me, my American dream right now is just to not have loans by the time I'm 30.

JUDY WOODRUFF: Back in Bethlehem at a Liberty High School Football game, 14-year-old Cora Morick (ph) played the piccolo with the Grenadier Band, her parents proudly watching from the stands.

This is the same high school Cora's grandmother, Roxanne Williams, attended.

But while Roxanne says she achieved her American dream, she has concerns for Cora.

ROXANNE WILLIAMS: I feel that she will have more challenges, that her options may not be as wide.

I just wonder if there are going to be enough jobs.

JUDY WOODRUFF: Here in Pennsylvania, we heard mixed views about the future of the American dream.

But David Leonhardt remains optimistic.

DAVID LEONHARDT: I think it's important to remember that most of the world looks at the United States quite enviously.

There is a reason that so many people want to move here.

And so we have a lot of problems.

We also, as a nation, have huge and perhaps unique strengths.

And in this time of national self-doubt, I think it's important both that we look honestly at our problems and retain some of that old-fashioned American optimism that we can solve those problems.

JUDY WOODRUFF: After all, optimism, a belief in a better tomorrow, is at the heart of the American dream.

For the "PBS News Hour," I'm Judy Woodruff in Bethlehem, Pennsylvania.