(Victoria Walker/The Washington Post)

When former vice president Joe Biden announced a few days ago that he was setting up a new political action committee called American Possibilities, the political world read it as a signal: He’s seriously thinking of running for president in 2020.

Then again, Dwayne “The Rock” Johnson got the same reaction when Hollywood’s highest-paid star told GQ magazine that running for office is “a real possibility,” though it’s not clear what party — if any — he would claim.

As did Facebook founder Mark Zuckerberg, when he set out to meet people in every state and dropped in for dinner with an Ohio Democratic family that voted for Donald Trump.

Go ahead and groan. Yes, the two nominees from 2016 are still trading fire about the election’s results, and the 2020 Iowa caucuses are still more than 30 months away.

But presidential buzz seems to be building around an unusually large and varied group of Democrats and famous names from outside of politics — a parlor game that includes pretty much every current Democratic senator and governor, mayors and House members, barons of the business world and, of course, the occasional wild-card celebrity. The Hill newspaper recently tallied 43 people who might run against President Trump.

This is a country, it has often been said, where anyone can grow up to be president. Last year, a billionaire reality-TV star with no government experience proved that to be true.

“How can you possibly tell someone they shouldn’t run for president? There’s no one on the planet who you can tell, ‘That’s crazy,’ ” said Jennifer Palmieri, a presidential campaign veteran who was communications director for Hillary Clinton in 2016.

There is more at work here than the sheer improbability of Trump’s election.

The president’s low poll numbers suggest a real opportunity for whomever the Democrats pick as their standard-bearer.

“Everybody assumes that Trump will be dead meat by 2020,” said former Democratic National Committee chairman Don Fowler.

And for the first time in at least a generation, the race for the nomination appears wide open, with no presumed early front-runner to be overcome in a Democratic primary. Conspicuously absent from the preseason handicapping is anyone named Clinton.

The nomination will be “a very inviting prize to have,” said David Axelrod, who was Barack Obama’s chief strategist in 2008 and 2012. “It is more expeditious to put together a list of Democrats who are not thinking they are running for president in 2020, than ones who are.”

Beyond that, “it’s only a matter of time until a Donald Trump runs as an independent and swamps both parties,” said Joe Trippi, a longtime Democratic operative who managed Vermont Gov. Howard Dean’s insurgent 2004 campaign.

It has been decades since the landscape appeared so fluid and unpredictable for Democrats. Back then, however, the forces worked in reverse from today’s dynamic.

Going into 1992, the party’s biggest names — most notably, New York Gov. Mario M. Cuomo — took a pass on the race, scared off in part by then-President George H.W. Bush’s stratospheric poll numbers.

Instead, the nomination went to a little-known governor from Arkansas, Bill Clinton, who went on to win the White House when a recession brought Bush’s popularity crashing to Earth.

The lesson, which would-be candidates have taken to heart ever since, is not to hesitate. It was reinforced in 2008, when Obama, a first-term senator from Illinois, won the Democratic nomination over prohibitive early favorite Hillary Clinton.

Politics takes a circular path sometimes: A quarter-century after his father declined what in retrospect looks like his biggest opportunity, Cuomo’s son Andrew, now himself the governor of New York, is among those being talked about as a 2020 possibility.

But any survey of likely candidates has to begin with a look backward, at people who have run before. One old joke has it that the only cure for presidential ambition is embalming fluid.

Former Maryland governor Martin O’Malley, the distant third-place finisher in the 2016 Democratic primary, has been the most active of the presumed hopefuls. He has shown up in 13 states since the election, campaigning and raising money for candidates, and speaking at party dinners.

O’Malley “made friends here,” said former DNC head Fowler, who lives in South Carolina. “There are some people here who have an affinity for him.”

Should Biden decide to make a third bid for the Oval Office, he would be “first among equals, even at this stage in life,” Axelrod said. At 74, the former vice president is four years older than Trump, who is himself the oldest first-term president in U.S. history.

Others argue that Sen. Bernie Sanders (I-Vt.), 75, would have the pole position, by virtue of his 2016 performance and his legions of liberal supporters.

“He hasn’t made up his mind,” said former Sanders campaign manager Jeff Weaver. “He’s open to it.”

So, many liberals hope, is Sen. Elizabeth Warren (D-Mass.), who has been touring the country to promote her latest book. At a fundraising dinner last month for a local NAACP chapter in Detroit, Rep. Maxine Waters (D-Calif.) introduced Warren as the woman “who might just be the next president.”

Yet there is also a longing for fresh new faces. And while the Senate and governor’s mansions are traditional launchpads for presidential nominees, this time around could see an opening for mayors such as Mitch Landrieu of New Orleans or Eric Garcetti of Los Angeles, or highly visible House members, such as Seth Moulton (D-Mass.) or Adam B. Schiff (D-Calif.).

What Democratic leaders do not want to see this time is a repeat of what happened to the Republicans last year.

With 17 declared candidates, the GOP debates became roller-derby-like spectacles. The sheer size of the field created an opening for a candidate like Trump to stage what amounted to a hostile takeover of the process.

“That’s great that there are 38 [potential Democratic candidates] thinking about it, but once you hit Labor Day 2019, I hope it shakes down to a manageable few,” said New Hampshire party chairman Raymond Buckley.

Former New York mayor Michael Bloomberg, who at one point considered an independent bid in 2016, warned in an interview with New York Times columnist Frank Bruni that if there are too many Democrats running, “they’ll step on each other and reelect Donald Trump.”

Bloomberg set the odds at “a 55 percent chance he gets reelected.”

The prospect of the kind of mogul-to-mogul matchup that Bloomberg took a pass on last time is tantalizing.

That is why names come up like those of former Starbucks chief executive Howard Schultz, Dallas Mavericks owner Mark Cuban and lifestyle empress Oprah Winfrey, who caused a sensation earlier this year when she joked — or did she? — that Trump’s election made her think she might be more qualified for office than she thought.

But seasoned operatives are skeptical that the party will ultimately turn to a Trump-like outsider.

“I don’t doubt that billionaires will start seeing presidents in the mirror, the way senators do now,” said Tad Devine, a longtime Democratic consultant.

But he added: “People don’t want another Trump on our side. They want to get as far away from him as possible.”

Axelrod agreed: “I don’t think you beat Trump by coming up with our own version of Trump. What is it that people find lacking in Trump? They find him lacking in experience, and lacking in knowledge of how government runs.”

Also likely to be important to Democrats is finding a candidate whose demeanor presents a contrast to Trump, and one with an inclusive unifying message.

For now, most of the possible contenders are demurring when asked about their plans for 2020.

A few — such as Virginia Gov. Terry McAuliffe — own up to the fact that they were thinking about running for president. But an establishment figure may start out at a disadvantage at a time when most of the party’s energy seems to be with “the resistance” to Trump.

Trippi says the Democratic primary field could sort itself into two groups.

“In early states, where you whittle down the field, there may be a governor or a senator who knows how to get things done, versus someone from the outside, and that’s the race,” Trippi said. “Now that so much is online, the opinions of someone posting from their basement in Anaheim could have an influence in New Hampshire,” Granite State party chairman Buckley said. “The old rhythms are thrown out the window.”

Traditional ways of campaigning, meanwhile, may be disrupted — putting less of a premium on money, and on the need to spend months or years getting to know local political leaders and grass-roots activists in the early states.