New York City Mayor Bill de Blasio is joining the two dozen other Democratic candidates running for president and many of us can only ask, why? Why would another (usually white, often male) politician look at the field of highly qualified Democratic presidential candidates and think: You know what this race needs? One more.

Though each of these candidates surely thinks he or she has something unique to offer, the truth is that with this many people in the race, it’s hard to see what possible way there is to break out of a very crowded race. The recent additions to the packed Democratic field could be better described as ”a bay of milquetoast men running for president,” Lee Banville, a political analyst at the University of Montana, recently told Vox’s Ella Nilsen.

Sure, there are real reasons candidates like Montana Gov. Steve Bullock, Colorado Sen. Michael Bennet, or even Ohio Rep. Tim Ryan have entered a campaign that Joe Biden appears to be dominating — and that Bernie Sanders, Elizabeth Warren, Pete Buttigieg, and Kamala Harris are duking it out for double-digit polling numbers. After all, Biden’s support could always collapse. Paradoxically, the more candidates in the race, the more enticing it becomes to join because the number of delegates are awarded proportionally, dramatically lowering the bar for the potential to win.

There certainly is a strong degree of personal vanity too; some of these guys just look in the mirror and say “I’m just born to be in it.”

But maybe the most important reason the field is so damn crowded is that the Democratic Party is still sorting through an identity crisis in the aftermath of 2016. A host of candidates look at recent history and think: The Democratic Party doesn’t really know what it’s looking for, and in this time of chaos, maybe the answer is me.

The plainly political reasons so many people are running for president

We asked Kyle Kondik, who helps run the University of Virginia’s Center for Politics, why a politician would decide to jump into the 2020 campaign when there are already 20 other candidates. He named three factors.

1) There isn’t exactly a big favorite.

“There’s not really a big favorite for the nomination. Biden may become that, but he’ll need to prove it,” Kondik says. “A dominant frontrunner is a barrier to entry for candidates, and this field has lacked that and arguably still does.”

Yes, Biden is substantially leading the polls — though he still doesn’t yet have a majority of primary voters — but it wouldn’t be a shock if he became the Democratic nominee. Plenty of other early frontrunners like Mitt Romney in 2012 and Hillary Clinton in 2016 have more or less sailed to the nomination. But just as many others have faltered. Take Rudy Giuliani in 2008, for example, or Jeb Bush in 2016 (even though he admittedly never polled that well).

But Biden’s certainly got some liabilities, and his presidential campaigns have flamed out before. If that happens, the race really does look wide open — which might make it attractive for a Bullock (a white man with a populist but center-left sensibility) to dip his toes in the water.

2. With so many candidates already in, why not take the chance?

“It may be that the sheer number of candidates has the effect of enticing even more candidates to enter. With every additional entry, hypothetically that means that the share of the vote needed to win Iowa or New Hampshire goes down,” Kondik says. “It’s not hard for any of them to imagine winning a quarter of the vote in an early state, which may be all it requires to win.”

Remember, the Democratic Party awards delegates in every state proportionally. You have to hit a certain threshold — 15 percent — to win delegates, but, as Kondik notes, politicians who have won statewide elections or who became the mayor of America’s biggest city on a long-shot comeback can certainly talk themselves into believing their talents can get them to 15 percent. At worst, they could win some delegates and become a power player at an unlikely but conceivable brokered convention.

3. Democrats really think they can beat Donald Trump.

“Democrats likely feel that the nomination is worth having — namely, that Trump is beatable in a general election,” Kondik told us. “If the incumbent president was more popular, my guess is that fewer people would be running.”

The payoff here is huge. Sure, Trump might have some built-in advantages as the incumbent, but he’s an incumbent who is historically unpopular considering the state of the economy. He sure seems vulnerable.

Dave Hamrick, who ran former Maryland Gov. Martin O’Malley’s presidential campaign in 2016, also noted the attention a candidate could generate as a White House contender. Nobody might care what an everyday Congress member about thinks about any given subject but a presidential candidate? That can get you on CNN or MSNBC.

You also have issues candidates, Hamrick said. Washington Gov. Jay Inslee, relentlessly focused on climate change, is a good example. Bennet, a proud pragmatist, is another candidate with some clear ideological rationale for his long-shot run. And with the rise of out-of-nowhere candidates like South Bend, Indiana, Mayor Pete Buttigieg, many think, why not take the chance?

“Nobody knows who’s going to win this primary. It’s completely open,” Hamrick said. “There are a lot of Democrats here that can all look at themselves and say, ‘It could be me. I’m qualified. I have as good a story as anyone. It could happen.’”

Why there are (still) so many white men running for president

After the 2018 midterm elections — dubbed the year of the Democratic woman — delivered the most diverse map of elected officials in US history, it’s worth noting that of the 22 Democrats running for president, only six are people of color and only six are women. One is both.

It’s the most diverse field of presidential candidates ever, but Reps. Seth Moulton, Tim Ryan, and Eric Swalwell, Sen. Bennet, and Gov. Bullock all got in anyway.

There is some research on gender and politics that helps explain this dynamic. For one, the stereotypical expectation of the role is intrinsically tied to men and masculinity; after all only men have served as president of the United States (and only one ever was nonwhite).

Second, women are much less likely than men to even begin to consider running for office, and when they do, they consider many more factors than men. “Men of all types felt more freedom to launch a candidacy,” according to a Washington University study by political scientists Richard Fox, Jennifer Lawless, and Courtney Feeley. This disparity starts at an early age; in a 2013 study, young men were twice as likely as women to have thought about running for office “many times.”

Men see officeholders who look like them, and they’ve likely thought about running for president before, regardless of whether someone urged them to, and they’re more likely to have considered fewer other factors — like potential risks — before jumping in.

Interestingly, in the runup to 2020, when the focus was on the slate of diverse candidates gearing up to compete, conventional wisdom indicated Democrats would need a new approach to beating Trump.

“There is a willingness to say the best contrast to [Trump] is a woman, and maybe a woman of color,” Kelly Dittmar, a political scientist with Rutgers University, told Vox earlier in the year. That no longer appears to be the case.

Democrats are going through an identity crisis

The 2016 primary was so dramatic because it boiled down to a binary choice between the mainstream liberal Hillary Clinton and the socialist populist Bernie Sanders. When Clinton beat Sanders only to lose to Trump, Democrats felt they had to seriously recalculate.

Sanders — a very unorthodox heir to the “candidate who finished second last time gets the nomination this time” trope — is trying to claim victory on the ideas front; in many ways, he’s right. The field now largely backs a $15 minimum wage, major changes to the American health care and higher education systems, and abandoning trade agreements the party’s last president negotiated. Democrats have a lot of candidates who now back a decidedly progressive platform, including Sens. Kamala Harris, Elizabeth Warren, Cory Booker, and Kirsten Gillibrand. Others, like Biden, Bennet, and Colorado Gov. John Hickenlooper, have shored up the more traditional moderate flank.

While these left-wing ideas have dominated the conversation around Democratic politics for the greater part of the past four years, they still represent a radical shift in a party that only three years ago selected a nominee that didn’t back a $15 minimum wage or single-payer health care.

Joe Biden is saying Obama-style politics were good. Amy Klobuchar wants to tell you that she can work across the aisle. The party has different ideologues, like Bennet and Inslee, even de Blasio. (You also have the pragmatists, like Bullock). California Rep. Eric Swalwell is sounding a very particular kind of national security message.

We don’t know what exact alchemy Democratic primary voters will come up with if they decide they don’t want to stick with Biden. Republicans endured some version of this in 2016, having gone with the consensus choice in 2012 and then lost an election they really thought they were going to win. It was a genuine identity crisis — remember the autopsy in 2013?

Under Trump, Democrats haven’t had to build meaningful consensus around policies — only rally around vague slogans. The Democratic Party doesn’t know what the consensus is. The candidates know this.

“They fill a lane where they think the party is going,“ Hamrick says. “Nobody can handicap this one. Nobody can predict it.”