By Election Day, ambitious Democrats had already resigned themselves to an eight-year wait for their chance in the national spotlight. Hillary Clinton was an overwhelming favorite against Donald Trump and, assuming she won, running a primary challenge against her in four years would be a fool’s errand.

Then Clinton lost.

Although this most stunning upset in modern presidential history has produced (and will produce) a thousand aftershocks, one of the most unlikely and important is that the Democratic presidential nomination in 2020 is now open.

That opening is made all the more remarkable by the fact that there is simply no logical heir (or even heirs) to President Obama or Clinton — no obvious candidate waiting in the wings to step forward and rebuild the party. Vice President Biden appears to have decided that he is done running for office. As a two-time loser, Clinton is done, too. And after that, the bench is, well, pretty thin.

Politics, of course, abhors a vacuum. So candidates will run. Here is a look at who they might be:

Sen. Cory Booker: Booker has been a national figure since the mid-2000s, when he was elected mayor of Newark. His résumé — football at Stanford University, a Rhodes scholarship — is impressive, and many Democrats see the young (he’s 47), charismatic, African American U.S. senator from New Jersey as the second coming of Obama. But the campaign that Booker ran for the Senate in 2013 was more competitive than it should have been largely because of his shaky performance. He may start the 2020 race as the front-runner, but he still has lots of questions that need answering.

Sen. Kirsten Gillibrand: Gillibrand may be the most logical heir to Clinton in the 2020 field, but it remains to be seen whether that is a good thing. When Obama chose Clinton to be secretary of state, Gillibrand was appointed to her Senate seat in New York and then won two subsequent elections to hold the seat, thanks to rock-star-level fundraising. Gillibrand, according to the New York Post, is already feeling out some of Clinton’s major donors about what comes next for the party. At 49, Gillibrand is one of a handful of women primed to be the next generation of female leaders for Democrats.

Sen.-elect Kamala Harris: Harris will not officially become a U.S. senator from California for more than a month, but she is already regarded as national-candidate material in four years. It is not hard to see why. She is the first African American woman elected to the Senate since Carol Moseley Braun in 1992. Harris also represents the largest and most Democratic state in the country, a huge financial launchpad to a presidential bid. (Through mid-October, Harris had raised more than $13 million for her Senate candidacy.) Her law-and-order background — she was elected and reelected attorney general in California — also will appeal to many Democrats. Whether Harris wants to — or will be ready to — run for national office so soon after being elected to the Senate remains to be seen.

Gov. John Hickenlooper: The Colorado governor was almost Clinton’s vice-presidential pick this time around. And in a field filled with Washington types, the governor of a swing state in the West could have real appeal. Hickenlooper also has a terrific life story — a Denver brewery owner who became mayor and governor — and a down-home demeanor that screams, “I am not a politician.” Hickenlooper’s biggest problem as a candidate may be that he is viewed as too moderate for the current Democratic Party. But some governor (Missouri’s Jay Nixon? Delaware’s Jack Markell?) will run for president, and, at the moment, Hickenlooper seems first among equals for that role.

Sen. Amy Klobuchar: Like Gillibrand, Klobuchar is an accomplished and ambitious senator who cuts the sort of profile that should put her in the mix for 2020. Unlike Gillibrand, however, Klobuchar represents Minnesota — not exactly a fundraising hotbed for a national candidate. But she has a very interesting legislative background — she worked with Rep. John Kline (R-Minn.) on ensuring veterans got the leave benefits they were promised before deploying, and she is a leading voice on adoption in the Senate.

First lady Michelle Obama: Let’s say this first: The soon-to-be-former first lady has never run for elected office and, to date, has shown absolutely no interest in doing so. But let’s also say this: She gave the two best political speeches of the past two years — the first at the Democratic National Convention in July, the second in New Hampshire in the fall, an emotional condemnation of Trump’s America. Obama has one thing — with the possible exception of Booker — that the rest of the people on this list lack: true star power. She would start the race not only totally known by base Democrats but also absolutely beloved. The issue for Obama is that being a candidate in your own right is very different from being a surrogate for a candidate.