WASHINGTON — The 2020 Democratic presidential primary hung a left turn out of the gate, leaving the middle of the field wide open for ... someone.
"We really, really don't know yet," said Matt Bennett, a vice president of the centrist Democratic think tank Third Way.
He's not panicking this early in the election cycle.
"This year will be about playing to the activists on Twitter and online donor universe. Next year will be about winning votes, and those are very different universes," Bennett said.
In 2016, it was progressives who were left waiting, begging even, for a champion to enter the ring against the front-runner, Hillary Clinton. First, they tried to draft Sen. Elizabeth Warren of Massachusetts, then they rallied around Sen. Bernie Sanders of Vermont as the non-Clinton alternative.
This year, though, progressives have an embarrassment of riches, with Warren and perhaps Sanders back to set the pace and fresher faces like Sen. Kamala Harris of California, among others, embracing single-payer health care and other left causes with a convert's zeal.
Now it's moderate Democrats who are left waiting and worrying about finding a nominee who they think can beat President Donald Trump.
One potential contender for those unsatisfied with their current options is Sen. Amy Klobuchar of Minnesota, who announced her candidacy on Sunday.
Michael Bloomberg, the billionaire former mayor of New York, has slammed the liberal candidates' soak-the-rich tax plans as he weighs a bid. And ex-Virginia Gov. Terry McAuliffe, who knocked the "dishonest populism" of the left in a recent op-ed, may enter the contest in March.
But everyone is living the shadow of former Vice President Joe Biden, who comfortably leads polls of the nascent Democratic field.
"That (moderate) lane would be secured if the vice president makes the decision to get in," said Harold Schaitberger, the longtime president of the International Association of Fire Fighters and vice president of the AFL-CIO.
Members of the firefighters' union voted narrowly for Barack Obama in 2008 and 2012, but broke heavily for Trump in 2016, according to an internal poll conducted by the union and shared with NBC News.
If Biden doesn't run, the 316,000-strong union will look for someone who can appeal to "pragmatic" and "middle of the road" voters, many of whom had once been reliable supporters of Democrats, Schaitberger said.
"I believe that for the Democratic nominee to win, it's going to take a nominee that can actually reach the electorate in between the two coasts," Schaitberger said in an interview. "We would have great difficulty considering or embracing a candidate from that far left, liberal side of the spectrum."
That's a sentiment shared by many of the party's donors and other gatekeepers, who will look for someone to fill the void left by Biden if he passes on running again, as he did in 2016.
"Others are waiting to see what Biden does. He's polling so strongly that they think if he is in, they can't get far," said David Brock, who runs a network of Democrat-aligned groups and just returned from a donor conference he hosted in Palm Beach, Florida. "There is definitely a space for a candidate who is solidly progressive, but more toward the center."
Their numbers are waning, but about 35 percent of Democrats still call themselves moderates while another 13 percent identify as conservative, according to a recent Gallup survey.
At the moment, however, seven of the eight major declared candidates support Medicare for All, which has prompted some uncomfortable questions on whether they are really prepared to eliminate all private health insurance.
The pileup on the left led Trump to raise the specter of socialism in his State of the Union Address last week and make comparisons to Venezuela, while ex-Starbucks CEO Howard Schultz says there is no longer room for him in his former party, leading him to consider an independent presidential run.
When Pew asked Democratic-leaning voters last month which direction they'd like to see their party move, 54 percent said "more moderate" compared to 40 percent who said "more liberal."
"Are any 2020 Presidential candidates paying attention to this?" asked former Sen. Claire McCaskill, a Democrat who lost re-election in Missouri last year, on Twitter.
But many mainstream Democrats think Schultz' claim that the left has taken over the party is ludicrous. They point out that in the midterm elections in November, progressive insurgents fared poorly in swing districts in both primaries and the general election.
The most important issue on the mind of most Democrats right now, according to polls, is "electability."
"We're going to look for that candidate that we think can best beat Trump — period," said Robert Wolf, the former chairman of UBS and a major Democratic donor who served as an economic adviser to President Barack Obama.
"For me, it's going to take someone who supports progressive issues like gun reform and climate change, but must be a pro-growth Democrat to win on the economy," Wolf added.
Of course, electability is a fuzzy concept after the surprise result of the 2016 election, and progressives and people of color have been challenging the conventional wisdom that appealing to the center is party's best strategy.
It's also unclear if moderate Democrats could coalesce around one candidate in the primary since they include a wide range of groups with cross-cutting values: religious African-Americans and Latinos with more conservative views on abortion; cosmopolitan professionals who want to fight climate change and the gun lobby but keep taxes low; and noncollege educated whites who might be OK with guns rights and soaking the rich.
So some candidates will likely be able to appeal to moderates for personal or demographic reasons, even while running on a progressive platform.
For instance, one name being floated by centrist Democrats is Sen. Sherrod Brown of Ohio, one of the Senate's most liberal members who nonetheless consistently wins re-election in an increasingly red state, which also happens to be a key presidential battleground.
Brown, who is currently testing the waters by touring early primary and caucus states, has made a point of refusing to join the bandwagon in support of Medicare for All and the Green New Deal, the environmental plan popularized by Rep. Alexandria Ocasio-Cortez, D-N.Y.
"His policies come from what effect it will have on a worker," said Nan Whaley, the mayor of Dayton, Ohio, who is trying to draft Brown into the 2020 contest. "And that is very different from everybody else, where the example is some Scandinavian country. That does not relate to a nurse working over in Miami Valley Hospital in Dayton, Ohio — what do they care about a Scandinavian policy?"
Ultimately, though, the party's nominee will likely have to transcend labels.
That's led some moderates to express interest in a candidate like Beto O'Rourke, the former congressman who defies simple ideological categorization and ran a Senate race in Texas last year on a hopeful message that allowed people to project their own values onto him.
"We don't need a clear winner on where we are on the ideological spectrum," said Iowa state Sen. Jeff Danielson of his state's first-in-the-nation caucuses, now a year away. "What we need is a clear winner on the message we'll deliver to the American people of where we go together."