With Thursday’s Democratic debate at Texas Southern University in Houston, the contest for the party's presidential nomination enters a far more focused phase.

For the first time, all the candidates who met the fundraising and polling requirements set by the Democratic National Committee — 10 in all — will be on the same stage together for three hours.

Gone are an equal number of other candidates, who were perhaps just as interesting (Where have you gone Marianne Williamson? Steve Bullock, we hardly knew ye), but ultimately distracting and with little if any chance of going the distance.

With the nation's first nominating contest, the Iowa caucuses, more than four months away, each candidate on the stage Thursday can still claim a viable path to the nomination. The debate poses perhaps the best chance yet for those candidates struggling to gain traction, including the two Texans in the race — Beto O'Rourke and Julián Castro — to make their case.

The odds against any one of those at the ends of the stage are daunting, but history suggests decent chances at least one longshot candidate will make a surprising run.

Here's a rundown of each candidate in the debate:

Joe Biden

RealClearPolitics polling average: 30.1%

If this debate is a gathering of the Democratic family, Biden, Uncle Joe, is the patriarch — respected, beloved, even cherished, if sometimes with an eye-roll because he is, as always, prone to gaffes. So how does one know when to worry if, as President Donald Trump said this summer, "Joe Biden has truly lost his fastball," and the safest bet to beat Trump — which is, after all his calling card — is not the safest bet at all.

He has run for president twice before, and it didn't go well either time. When he sought the nomination in 1988, he talked his way out of the race — he had borrowed the rhetoric of a British Labor Party leader without attribution — at right about this point in the election calendar — September 1987. Two decades later, seeking the 2008 nomination, he lasted a little longer, dropping out after collecting 1% of the vote in the Iowa caucuses.

But of course that time, the winner, Barack Obama, picked Biden as his running-mate, to serve eight years as vice president. But, as his tenure drew to a close, and while mourning the death of his son, Beau, Biden passed on challenging Hillary Clinton, who lost to Trump in 2016. This time around, for all his bumps in the road, Biden's lead against his rivals and in matchups with Trump, have held steady. But he is 76 — 77 in November — and his mission Thursday is to come through those three hours having reassured Democrats that he's still got what it takes.

Elizabeth Warren

Polling average: 17.6%

Warren, 70, comes into Thursday's debate on the best trajectory of any of the candidates, now slightly ahead of Bernie Sanders, her stiffest rival for the progressive energy in the party that, fully harnessed, could propel a candidate to the nomination, even in a showdown with Biden.

Last October, four months before she announced her candidacy, Warren seemed dead in the water. In answer to Trump's relentless hazing of her as “Pocahontas” for what appeared to be an errant claim when she was younger of some American Indian ancestry, she had taken a DNA test that didn't seem to prove what she thought it did, and that left some observers wondering whether she lacked the political gene that would enable her to effectively challenge Trump.

When she wasn't being derided as Pocahontas, she was being derided by critics as a schoolmarmish scold or a rerun of Hillary Clinton.

But 128 town halls, more than 52,000 selfies, and 103 media availabilities later, Warren has proven to be a warm and lively candidate, immersed and well-versed in policy with a knack for narrative and explication, and a compelling personal story from her hardscrabble Oklahoma upbringing.

A Republican until middle age — she first registered as a Democrat at 47 when she was a Harvard University professor — Warren says she's a capitalist, but with policies, including a wealth tax and plans to break up big banks and Big Tech, that might scratch a Democratic itch for some radical change.

Bernie Sanders

Polling average: 16.9%

No matter what happens, everyone on the debate stage will have achieved something monumental, and no one more so than Sanders. In the 2016 campaign, Sanders, 77, a brusque, cranky self-described democratic socialist with a thick Brooklyn accent even after nearly half a century living in Vermont, created a movement powered by young people, which brought what had been considered radical ideas into the Democratic mainstream and nearly toppled Clinton, the overwhelming establishment choice. This time around, his calls for Medicare for all and free college are nearly dogma among progressives.

His numbers aren't what they were at his peak, but, right now, in a crowded field, they do not need to be. However, for the many not enamored of Sanders, and for others for whom defeating Trump is all that matters, asking America to choose between Trumpism and socialism is simply too great a risk to run.

Sanders' mission Thursday is to remind Democrats that authenticity is what matters and that there ain't nothing like the real thing.

Kamala Harris

Polling average: 6.7%

Harris, 54, the charismatic daughter of an immigrant father from Jamaica and an immigrant mother from India, had two spectacular we-have-a-winner moments so far in the campaign. There was her picture-perfect campaign launch rally in Oakland, Calif., in January before a crowd of 20,000, larger than Obama's vaunted kickoff in Springfield, Ill., a dozen years earlier. And then there was what seemed a well-executed attack on Biden on race and busing in the first debate.

Harris, a former district attorney and attorney general, known in the Senate as a sharp interrogator, was celebrated as having proved herself uniquely qualified to prosecute the case against Trump. Her poll numbers soared.

But as time passed, Biden's numbers didn't suffer, Harris' attack seemed too cutthroat and too personal, and her numbers tumbled, especially after she found herself blindsided by an attack in the second debate on her muddled health care position and her record as a prosecutor by U.S. Rep. Tulsi Gabbard, the Hawaii Democrat who is still in the race and hopes to regain a place on the next debate stage if her poll numbers improve by October.

Having risen and fallen on her debate performances, no candidate has more riding on Thursday's event than Harris.

Pete Buttigieg

Polling average: 4.4%

Mayor Pete is already a winner. How many candidates get to be known by their title and first name only?

He is 37. He graduated from Harvard University, was a Rhodes scholar and served in Afghanistan.

He was the Democratic candidate for state treasurer in Indiana in 2010 and received 37.5% of the vote.

He was elected mayor of his hometown of South Bend, Ind., in 2011, the 299th largest city in America, at about 100,000 and shrinking, a little smaller than Wichita Falls.

He came out as gay and was reelected mayor in 2015. He ran for chairman of the Democratic National Committee in 2017, but dropped out before the vote. He married his husband, Chasten, in 2018. He announced for president in April, and on the strength of an uncommon calm, poise and preternatural eloquence, built on generational promise and spiritual grace notes, rocketed into the presidential race, surging in the polls, effectively undoing Beto O'Rourke's momentum, and, most remarkably, raising more money than anyone in the field in the last quarter.

His numbers have since come down to Earth, but he could play very well in Iowa, and his mission Thursday is to drive home his central message, that he, better than any other candidate, embodies the generational change that could leapfrog America past this sour, polarized era.

Andrew Yang

Polling average: 2.6%

Yang, 44, is the one who is unlike any of the others, with no previous elective experience.

"We need to do the opposite of much of what we're doing right now, and the opposite of Donald Trump is an Asian man who likes math," Yang said in the opening statement at the second debate in late July in Detroit. Instead of MAGA hats, his supporters have blue MATH hats: Make America Think Harder.

His campaign is focused on a central concern, that in the next 12 years automation threatens the jobs of 1 in 3 U.S. workers —a "fourth industrial revolution" — and that a universal basic income is needed to get the American people through the dislocations that will ensue.

That idea, and Yang's exposition of it, has drawn a dedicated following that provided him with the polling and fundraising numbers to get on the debate stage, a remarkable achievement. What he does now remains to be seen.

Cory Booker

Polling average: 2.4%

Booker, 50, seeks to follow in Obama's footsteps in becoming the second African American to win the White House. He tends to be more emotional, looser than Obama, but not as cool.

In 2008, Obama came from behind to defeat Clinton in Iowa. Having won with white voters in Iowa, black voters in South Carolina switched allegiances and handed Obama a big victory there. Right now, Biden has a commanding lead with black voters nationally and in South Carolina.

But, if Booker, who has an excellent organization in Iowa, surpasses expectations there, if Biden fades and if Harris stays stalled, Booker could get a big lift in South Carolina just ahead of Super Tuesday, and then, who knows?

Beto O’Rourke

Polling average: 2.1%

O'Rourke, 46, has maybe had the worst polling trajectory of the 10, peaking the day he announced, plunging soon after in both national and early polls, where he has been mired in low single digits ever since. But you wouldn't know that from the crowds he draws, the passions he excites and his own increasingly feverish commitment to the race. Most especially in the aftermath of the Aug. 3 massacre in his hometown of El Paso by a gunman intent on killing Hispanics, O'Rourke, always a free spirit, has become emotionally and politically unbound, using the f-word with abandon to demonstrate the urgency of dealing with the epidemic of gun violence, including mandatory buybacks of assault rifles. In other words, confiscation, a place Democrats, especially from Texas, have not in the past, generally gone.

On Thursday, O'Rourke, who traveled to all 254 Texas counties in an SUV during his 2018 U.S. Senate campaign, took a more carbon-friendly ride on a bus from New York to Boston, taping a podcast along the way.

He is doing it his way and, while his performance at the first two debates — not his most natural milieu — were flat, that's not likely to be the case Thursday.

Julián Castro

Polling average: 0.9%

Castro, the former San Antonio mayor and secretary of housing and urban development in Obama's second term, was the last of the 10 candidates to meet the polling marks need to make the debate stage. Castro is 44 and looks a lot younger. He says that people have always had a tendency to underestimate him.

Still little known and underfunded, he has run a disciplined, serious, policy-driven campaign. He has especially shined at the debates, effectively scolding O'Rourke at the first debate — "I think you should do your homework on this issue" — in an exchange on border policy, and calling out Biden at the second debate on the Obama administration's record on deportations — "One of us has learned the lessons of the past, and one of us hasn't."

Castro's ultimate argument, which he has not yet made on a debate stage, is that, because of his youth and ethnicity — he would be the first Latino president — he is the candidate best able to recreate the Obama coalition and "supercharge it." If he were the nominee, he asserts, Hispanic turnout would go "through the roof," enabling Democrats to win Arizona, Texas, Georgia and Florida. But it is an audacious claim, particularly in light of a Texas Lyceum Poll released in recent days in which Castro was the choice of only 4% of Texas Democrats and 7.9% of Hispanic Texas Democrats. Biden led the field, followed by O'Rourke, and O'Rourke led with Texas Hispanic voters.

Castro can be depended on to turn in another strong performance Thursday, and, more than any of the other candidates on the stage, with the possible exception of Buttigieg, his campaign has made him a formidable potential running mate, particularly if Warren is the nominee.

Amy Klobuchar

Polling average: 0.9%

Klobuchar's mentor is Walter Mondale, an accomplished if not very exciting liberal senator from Minnesota, who was picked by Jimmy Carter in 1976 to be his vice president and served a single term until they lost in 1980 by Ronald Reagan. In 1984, Mondale was the front-runner for the Democratic nomination and fended off a surprisingly strong challenge from rising star U.S. Sen. Gary Hart of Colorado. Mondale went on to lose every state but Minnesota and the District of Columbia to Reagan.

Klobuchar carries many of the same strengths and weaknesses as Mondale, but, in this case, Trump is no Reagan, Americans might be ready for a respite from the chaos of the last few years, and Klobuchar can argue that she knows the values and speaks the language of everyday Americans who can swing the election better than avatars of the Twitter-savvy coasts.