Nearly 650 days before the 2020 Presidential election, and it’s already made history.

Seven significant Democrats have declared their intentions to run; four of them are women. That’s unprecedented.

The field also already includes black, Hispanic, and gay candidates. Once other expected candidates jump in, their ages will range from 37 to 77. They will be Protestant, Catholic, Jewish, and Hindu, from as many as 17 states and the District of Columbia.

Yet the two dozen or so likely candidates, despite their record-breaking differences, are overwhelmingly similar—with traditional political qualifications, and broad agreement on policies and priorities.

That will pose a tough challenge for Democratic primary voters.

It’s also a knotty task for pundits trying to predict, a year before the opening contests in Iowa and New Hampshire, what those voters will do with nearly two dozen choices.

From this early vantage point, it might be easier to picture what type of candidate might appeal to the current Democratic Party electorate. A woman serving in the U.S. Senate seems like a good bet at this point; if not, then perhaps a state governor.

Below I’ve broken the field into six such categories, listed by likelihood of producing the nominee. Within each category, I rank the individual candidates’ chances.

1. Gentlewomen of the Senate
It was clear throughout the 2018 midterm primaries that, all else being equal, Democratic voters are eager to embrace a competent, qualified female candidate. As it happens, four very strong candidates—arguably the strongest contenders regardless of gender or position—happen to be women currently serving in the United States Senate.

Kamala Harris, U.S. Senator, California
It would be difficult to design a more perfect candidate for this nomination process than Harris. She is smart and accomplished, without too much of a paper trail of potentially controversial votes. Her statewide races in California, for Attorney General and Senate, have given her one of the best Democratic donor bases in the country—and, California’s new status as an early primary state could give her a big leg up. Her stellar Presidential campaign rollout this week has her holding the top spot of both pundit and betting lists of likely nominees.

Amy Klobuchar, U.S. Senator, Minnesota
Though she hasn’t yet announced whether she’s running, Klobuchar has been swiftly climbing the oddsmakers’ charts this month. That’s at least partly due to columns by CNN and Washington Post political data analysts declaring her most electable in a general election, based on her overperformance in her own 2018 purple-state re-election. Klobuchar is also the one major woman candidate not hailing from a stereotypical liberal coastal-elite state, which appeals to Democrats paranoid about losing upper-Midwest states against, as New Yorker Hillary Clinton did in 2016.

Elizabeth Warren, U.S. Senator, Massachusetts
It would be a mistake to underestimate Warren’s appeal among progressive voters, and she is already laying the markers for other candidates to follow, with policy positions, staffing, and fundraising. But, most Democratic voters see her firebrand liberalism as a risk in a national general election, at a time when they seem to be looking for a safer bet.

Kirsten Gillibrand, U.S. Senator, New York
Her candidacy announcement was overshadowed by Harris’s, but she’s well-prepared with big donor backing and early-state staffing (some of which she will likely announce in her New Hampshire campaign trip this coming weekend). Her reputation as an ideological moderate, which hurts her with many among the party’s base, could actually be something of a boon among the suburban women, of all races, who she seems to be targeting.

2. Governors
Individually, the state Governors potentially in the 2020 mix are less well-known, and less certain to even run, than some others named further below. But, it seems very likely that at least one of them will emerge as a serious contender, combining executive experience with campaigning skills. If Democrats aren’t quite ready to embrace the level of change represented by a woman or a Generation-Xer, there’s a good chance their best bet will look like one of these men.

John Hickenlooper, former Governor, Colorado
He hasn’t received the buzz of other candidates-in-waiting—I haven’t seen him crack the top 10 in any pundit rankings or betting sites—but Hickenlooper is a popular purple-state governor who’s been carefully planning his campaign for a long time. He’s got sufficient progressive credentials, but will run as a pragmatic, get-things-done centrist. And at 66 years old he’ll look experienced next to the Gen-X candidates, but fresh-faced compared with the septuagenarians.

Jay Inslee, Governor, Washington
With a similar profile to Hickenlooper but a more liberal reputation, Inslee’s chances might hinge on just how big an issue climate change has become for Democratic voters. That’s his bailiwick, and it just might help him stand out with activists, donors, and ultimately voters. He’ll need to play catch-up with candidates who have been building out their campaigns longer. He also needs to mend fences in New Hampshire, where establishment Democrats are angry that he spent little on that state last year as chairman of the Democratic Governors Association.

Steve Bullock, Governor, Montana
Young enough at 52 to represent generational change; a progressive Democrat re-elected on the same 2016 state-wide ballot that Trump carried by 20 points; Bullock is a great retail politician touted by some insiders as the perfect profile for the general election. That, in turn, has fundraisers in New York reportedly interested in backing the Montanan’s bid, which will require him breaking through in Iowa as fellow farmland folk. It sounds like a tough needle to thread, but he’s ready, well-staffed, and has a good story to tell.

Terry McAuliffe, former Governor, Virginia
It’s far from clear that today’s Democratic voters are looking for a consummate political insider and fundraiser running as a centrist while taking potshots at the “dishonest populism” of leading liberals. But don’t underestimate his appeal. The biggest question might be whether fellow members of the Clinton political machine decide to back him.

3. Generation-X Factor
Democrats on the outs have tended to turn their lonely eyes to younger, charismatic, Washington-outsider candidates representing generational change; or, at least they did in 1992 with Bill Clinton, and in 2008 with Barack Obama. A group of line-skipping hot-shots, born after 1970, are vying for that energy this time around; they might seem too untested for Democrats obsessed with electability.

Beto O’Rourke, former U.S. Representative, Texas
O’Rourke’s flame is burning so brightly after his close Senate loss, a Wall Street Journal column this week pondered the difficulties he’ll face as the Democratic frontrunner. Half of Democrats believe he’s destined to fade; the other half swears he’s the real deal.

Eric Swalwell, U.S. Representative, California
He looks the new-generation part; has gained allies all over the country through his House leadership; and hails originally from the crucial first-caucus state of Iowa. Of those hoping to catch lightning in a bottle, Swalwell is as well-positioned as any.

Julián Castro, former Secretary of Housing and Urban Development, Texas
Can you believe it’s been 12 years since Matt Santos, played by Jimmy Smits, won the fictional Presidency as a likeable Latino pol from urban Texas? The Castro young-hotshot campaign has seemed inevitable for so long, it’s hard for it to feel as fresh as it needs to. Still, he’ll get a very good look from activists and voters, and will have a chance to win them over.

Pete Buttigieg, mayor, Indiana
Calling him Generation-X might be a stretch; Buttigieg was born in 1982. A military veteran, much-praised mayor of South Bend, Indiana, and openly gay and married, Buttigieg fits the profile of successful 2018 Democratic U.S. House candidates. It’s not crazy to think those same voters might respond well to it in the Presidential race. He has a stronger network of institutional support than you might imagine, as shown in his unsuccessful 2017 bid to be Democratic National Committee chair.

Tulsi Gabbard, U.S. Representative, Hawaii
Once seen as a rising star in the party, but now eyed warily as a potentially disruptive oddity, Gabbard wouldn’t seem to have any available paths to the nomination. On the other hand, you’ll notice a dearth of women candidates aside from the four U.S. Senators, so perhaps if they flop Gabbard can shine.

4. Gentlemen of the Senate
This group, by itself, would normally be a pretty top-notch field of accomplished, qualified Presidential candidates. This year, they’re all starting in the second tier, hoping for a break.

Sherrod Brown, U.S. Senator, Ohio
A portion of the Democratic Party is always waiting for another Paul Wellstone—the beloved liberal anti-politician who clicked with rural voters, but died in a plane crash before his brand could be tested nationally. The regularity with which Brown is described as “rumpled,” as Wellstone often was, betrays the comparison. He’s the candidate for those who want a slightly younger and less goofy Joe Biden, and that might be exactly what the party wants.

Cory Booker, U.S. Senator, New Jersey
Booker has had trouble sparking Democratic voters’ interest so far, but he’s a fantastic retail politician with a top-notch campaign structure and plenty of fundraising ability. He could be one viral campaign moment away from being a top-tier contender.

Jeff Merkley, U.S. Senator, Oregon
Merkley, a solid progressive who backed Sanders in 2012, has been laying the groundwork for a Presidential campaign since 2017. Lately, however, he seems a little less likely to follow through—with indications that he might be finding the fundraising commitments scarce. If he does run, and gets the needed resources, he’ll be a compelling liberal option.

Michael Bennet, U.S. Senator, Colorado
Is there room in the Presidential race for more than one Denver-based Wesleyan University alumnus? Bennet, former chief of staff to fellow Cardinal Hickenlooper, seems to think so. He has a great Presidential resume, but it’s hard to see how he breaks out of this pack.

5. No Country for Old Men
For those who think Baby Boomers aren’t quite old enough to take responsibility, there are some strong contenders in their late 70s.

Joe Biden, former Vice President, Delaware
It wouldn’t be a Democratic Presidential nominating cycle without an Uncle Joe trial balloon, but it seems that 76-year-old Biden is determined on a third actual campaign for the ring. There are plenty of reasons to be skeptical that this one will end any better than the ones that went before. However, plenty of influential people consider him the frontrunner, and that could become a self-fulfilling view.

Michael Bloomberg, former Mayor, New York
What looked like a potentially crowded category of billionaires has winnowed down, apparently, to just Bloomberg: Howard Schultz has opted for an Independent candidacy, and Tom Steyer has decided to not run at all. Progressives won’t be interested in the centrist 76-year-old, and he knows it, but his shot at the nomination is not as far-fetched as many are assuming. He is, in effect, the legitimate version of Trump’s business-success political brand, and there is a constituency for that in the Democratic Party.

Bernie Sanders, U.S. Senator, Vermont
In a field of more than Hillary Clinton, it’s hard to see how Sanders holds onto most of his 2012 support, let alone expands it. The 77-year-old has surprised before, though.

6. Why Not Me?
It’s actually a bit surprising that we aren’t seeing more viable candidacies from less traditional paths: Wesley Clark type generals, or Carly Fiorina type business executives, for instance. These are the closest to that out there so far.

Mitch Landrieu, former mayor, Louisiana
He’s been talked about as a 2020 dark horse pretty much since the 2016 election. Many see him as a perfect fit to bring together the disparate parts of the old Democratic coalition, including the South. He hasn’t ruled out running, but he hasn’t been making moves either.

John Delaney, former U.S. Representative, Maryland
Delaney, who walked away from his House seat after three terms, is running more as an entrepreneur than a congressman. He’s been stumping in early states since July 2017, generating decent buzz.

Eric Holder, former U.S. Attorney General, Washington D.C.
Holder seems eager to run, and to try to capture some of the magic Democrats associate with the Obama administration. It’s hard to see his path to the nomination, though.