All 10 major Democratic candidates are appearing on stage together for the first time Thursday night in a debate that could shakeup what has been a fairly static presidential primary so far.
The two debates this summer did nothing to dislodge former Vice President Joe Biden from the top of the polls, but the field has begun to winnow and voters are increasingly tuning in, potentially giving challengers an opening in the ABC News-sponsored face off.
For three hours in Houston starting at 8:00 p.m. ET, Biden will hold center stage surrounded by rivals, whom recent polls show have settled roughly three tiers.
Biden's strongest challengers will flank him on stage, but are politically to his left: Sens. Bernie Sanders of Vermont and Elizabeth Warren of Massachusetts.
Biden and Warren have never been on stage together, but their surrogates and allies have taken some shots at each other in recent days, even though advisers to both insisted neither planned to attack.
Former Pennsylvania Gov. Ed Rendell, a prominent Biden supporter, published an op-ed in the Washington Post on Thursday attacking Warren as a "hypocrite" for letting him host fancy fundraisers for her in the past, even though she's attacked politicians like Biden for attending them now.
In the second tier are candidates who have had a moment in the spotlight, but since lost some luster.
California Sen. Kamala Harris saw a fleeting surgeafter attacking Biden on race issues in the first debate in June; Mayor Pete Buttigieg of South Bend, Indiana, has petered out a bit since his meteoric rise earlier this year; and former Texas Rep. Beto O'Rourke has begun to regain some lost ground by speaking bluntly about guns and racism after a shooting in his native El Paso.
Rounding out the stage are three candidates still hoping to climb above the low single-digits in polls.
Entrepreneur Andrew Yang is looking to continue his unexpected success and convince voters he's not just a novelty.
New Jersey Sen. Cory Booker has yet to translate his charisma and compelling biography into a polling bump.
And Minnesota Sen. Amy Klobuchar will try to persuade voters that her electoral success in the critical upper Midwest makes her the best candidate to take on President Donald Trump in October.
Eight other candidates did not qualify for this debate, but will have another shot to make the one next month in Ohio.