Five things to watch in tonight's Democratic debate

Ten Democratic presidential hopefuls will take the debate stage in Atlanta on Wednesday night, as the candidates look for a breakout moment to either cement their place in the race's top tier or elevate their campaigns from the lower rungs of the primary field.

The field's four leading candidates - former Vice President Joe Biden, South Bend, Ind., Mayor Pete Buttigieg, Sen. Elizabeth Warren (D-Mass.) and Sen. Bernie Sanders (I-Vt.) - are all jockeying to deliver a strong performance at the debate, hoping to give their campaigns a burst of momentum heading into 2020 and the Iowa caucuses.

They'll share the stage with six other candidates - Sen. Kamala Harris (D-Calif.), Sen. Amy Klobuchar (D-Minn.), Sen. Cory Booker (D-N.J.), former tech executive Andrew Yang, Rep. Tulsi Gabbard (D-Hawaii) and billionaire philanthropist Tom Steyer - all of whom are hoping for breakout moments of their own.

Here are five things to watch:


Can Warren quell concerns about her candidacy?

Warren's months-long rise to the top of the polls has seen its share of setbacks in recent weeks: Her rivals have repeatedly raised questions about how she plans to finance her proposed "Medicare for All," and Biden has attacked the Massachusetts senator as an "elitist" with a "my way or the highway" approach to politics.

Her lead has slipped in some polls in recent weeks. Meanwhile, other surveys suggest that Democratic primary voters are more eager to nominate a moderate candidate seen as having a better chance of beating President Trump.

Warren has taken some steps in recent weeks to alleviate voters' concerns about her reform-minded candidacy. Earlier this month, she released a plan that would avoid raising taxes on the middle class to finance her Medicare for All proposal and outlined a more gradual approach to health care that would preserve private insurance coverage for a transition period. 

Wednesday's debate will give her a chance not only to address lingering reservations about her electability and policy agenda before a national audience, but to take on critics, like Biden and Buttigieg, who are also competing for the top spot in the race.


Will rivals go after Buttigieg?

Buttigieg has gained momentum in recent weeks as he's pitched himself to moderate voters as a younger alternative to Biden while drawing sharp contrasts with his leading progressive rivals.

That message appears to be translating to support in Iowa, in particular. A Des Moines Register/CNN/Mediacom poll released over the weekend showed him taking a broad lead among likely Democratic caucusgoers in Iowa.

But that recent success is likely to make him a prime target for his opponents when he takes the debate stage on Wednesday night. There are already lingering tensions between Buttigieg and some of his fellow 2020 hopefuls, some of whom argue that the 37-year-old mayor is too inexperienced to be a viable general election candidate.

And despite his surge in Iowa, Buttigieg has struggled to gain the same kind of traction in more diverse early primary and caucus states.

In South Carolina, Buttigieg has struggled to break out of single digits in polls and fares even worse among black voters, who make up more than half of the state's Democratic electorate. A Quinnipiac poll released on Monday showed his overall support there at 6 percent. He registered less than 1 percent support among black voters in the survey.

Buttigieg may face a litany of criticism on Wednesday night over everything from his struggle to build a diverse coalition of support to his relative inexperience in the national political arena. 

The question that remains: Can Buttigieg take a punch?


Will moderates have their moment?

It's been a good few weeks for the primary field's moderate candidates.

They've begun pushing more aggressively against the progressive policy proposals of rivals like Sanders and Warren. Recent polls show Democratic voters leaning toward a moderate nominee. And the party scored a slew of key electoral victories this month in states like Kentucky, Virginia and Louisiana by running candidates with more moderate platforms.

Candidates like Biden, Buttigieg and Klobuchar will have the opportunity on Wednesday night to showcase the moderate resurgence and make the case that they're better positioned than their progressive opponents to beat Trump in 2020.

One recent development that could help bolster that argument: former President Obama, who remains one of the Democratic Party's most influential figures, recently warned the candidates against moving too far to the left.


Do the progressives fight back?

While the primary field's moderate hopefuls have gotten a boost in recent weeks, Sanders and Warren aren't ceding any ground. On the campaign trail, they've continued to make the case that Democrats need a progressive nominee to drive support among the party's core voters and oust Trump.

At the Nevada Democratic Party's "First in the West" dinner on Sunday, both Warren and Sanders asserted that the country was in need of transformative policies and a broad restructuring of U.S. politics, and swiped at those who advocate for more gradual change.

Sanders and Warren will have the chance to bring that argument to the debate stage once again on Wednesday, setting up a potential showdown between competing factions of the Democratic Party.

They'll also have an opportunity to push back against concerns from some voters - and fellow 2020 candidates - who see their proposals as too radical to play in a general election.


Do the 2020 newcomers weigh on the debate?

Looming over the debate is the entrance of two new moderate candidates, former Massachusetts Gov. Deval Patrick and former New York City Mayor Michael Bloomberg.

The two men previously flirted with presidential runs only to rule them out last winter. But sensing an opening in the current Democratic field, Patrick jumped into the contest last week and Bloomberg began taking steps to get on the ballot in several states with March primary dates.

To be sure, neither Patrick nor Bloomberg will be on stage Wednesday. But their presence in the Democratic field could end up weighing on the dynamics of the debate.

Candidates like Warren and Sanders have cast Bloomberg's and Patrick's renewed presidential ambitions as a sign that party elites and wealthy donors feel threatened by progressives. Meanwhile, others like Biden and Buttigieg are likely to find themselves in more direct competition with the two newcomers, who believe that they are better able to win over more moderate voters.

How - or whether - Bloomberg and Patrick enter the conversation on Wednesday will provide some insight into how they might impact the broader dynamics of the presidential race.