This week, the Democratic presidential sweepstakes gets its official start in two primetime showcases on NBC and Telemundo, even as the field continues to expand. Twenty contenders for the party's nomination will take the stage to debate in two separate panels. The leading candidates will try to bury the upstarts, and the longshots will try their best for Hail Mary plays that could vault them into the center of the national consciousness.

Unfortunately for everyone, the format of the debates almost guarantees that little else could possibly be accomplished. With two crowded stages, it's unlikely that any one candidate will get crowned a "winner," and perhaps it's unrealistic to expect any significant polling changes after the first event. At best, candidates can hope that a zinger or a quip will make one of their policy stances stand out; usually, the format rewards the biggest grandstander. The most potential for changing the direction of the race comes not from winning arguments on complex public policy issues but from personal attacks. What can we expect? That will depend on a number of factors, as well as just how desperate some might be to make a splash before going under entirely.

First, the moderators will likely take a significant amount of time from the attention-starved candidates. NBC and Telemundo plan to use five moderators on both nights, with NBC News anchor Lester Holt running the show. Savannah Guthrie and José Diaz-Balart will join Holt in the first hour, and Chuck Todd and Rachel Maddow will take their places in the second. Even with only three moderators at a time on stage, each will want their own chance to shape the direction of the debate. Maddow should be especially eager in this regard and we can expect the second hours of the debates to challenge all of the candidates to move to the left.

The biggest problem for the candidates is that, for the most part, all they'll be able to do is pledge fealty to progressivism in general. Even without the moderators eating up time, they'll barely have enough time to introduce themselves. Add in the moderators and their engagement, and any one of them would be lucky to get 10 minutes of actual speaking time. Republican veterans of the 2015-16 debates can attest to that.

Next, consider who has the most to lose in these debates. On Wednesday night, Elizabeth Warren will debate nine other candidates who are below the Mendoza line in polling, making her a prime target for everyone else on stage. The next-best polling contender on that first night is Beto O'Rourke, whose numbers have dropped off as Warren's have risen over the last few weeks. He and the other eight on Wednesday night will use what little time they have to attack both Donald Trump and the frontrunner Joe Biden, but Warren's polling also puts her in position to be the Biden Alternative they all desire to be. If they can rattle Warren, they might break out of the pack — or at least hope to do so.

Biden himself has the most to lose, but he goes into Thursday night with some advantages. First, Biden got matched up with fellow first-tier contender Bernie Sanders, whose numbers have also declined over the last couple of months but still leads the rest of the field. Biden has proven himself tough in debates in the past, although he has yet to experience this much of a crowd on the stage. After stepping into a mess over his remarks about working with segregationists, Biden can expect sharp attacks from the field, especially Kamala Harris, who has already been vocal about his comments. Still, Biden will have had plenty of time to prepare for those attacks and will have the advantage of already engaging with Trump publicly over his policies. Biden has the most claim on looking presidential, and his tenure as Barack Obama's vice president gives him the most credibility to run on party unity under the mantle of his leadership.

Meanwhile, Sanders' struggle will be continuing to distinguish himself from the rest of the field as they all, apart from Biden, run to the left. Four years ago, Sanders had that turf to himself and transformed the Democratic Party by being the default choice of progressive populists. This time around, Sanders has to figuratively and literally share a stage with younger and more diverse options for that choice, not to mention Warren's spotlight on night one. Sanders won't have the luxury of only attacking Biden; he will have to use his small slice of time to convince Democratic voters that he's the only authentic progressive on stage.

Who has the most to gain? Practically everyone else on stage. The other 17 people on stage have spent months and millions to run and have little to show for the effort, especially high-profile names like Harris and O'Rourke, who were expected to do much better than their polling shows thus far. Aside from Warren and Sanders, the Senate Democrats in the race have produced disappointing results, and the sitting governors have done even worse. The top three candidates have 61 percent of polling support in RealClearPolitics' rolling averages, leaving an average of 2.3 percent for everyone else on stage, less a point or two for the four non-qualifiers.

To break out in this debate will require grabbing the attention not just from the front-runners but also from the other candidates and the moderators. That will take arrogance and passion, and only a handful of the also-rans have enough of both. Watch for Cory Booker on the first night to demagogue his way to the center of the debate, with Julián Castro perhaps not far behind. Eric Swalwell barely qualified for this debate and might not make the cut again without some kind of breakout. Harris certainly will qualify for future debates, but her money might not hold up unless she delivers a big performance.

Most likely, though, this debate will not change the trajectory of the race much. There simply won't be enough time for anyone to make a claim on greater or lesser support in this format, and perhaps not even enough time for a proper introduction. If so, that will play in Biden's favor as the clear front-runner and eminence grise of the Democrats. Unless the former vice president finds new ways to insert his feet into his mouth, this debate is his to lose.