Joe Biden is the elephant in the room for the 2020 Democratic primary.
As the Democrats' 2020 field begins to take shape, the former vice president is looming over the race, with his decision on whether to run becoming an X factor for some potential 2020 Democrats, especially those who believe they will appeal to the same type of voters as the former Delaware senator.
Biden, according to a source familiar with the discussions, is poised to decide in the coming month whether he will jump into the Democratic presidential race, inching closer to answering the looming question of whether he will make a third bid for the White House. If Biden decides to run, he could wait until later this winter or even early spring to make a formal announcement.
Some possible Democratic contenders have told supporters that they will rethink their possible run if Biden jumps in. Some have been more direct, telling advisers they won't run if Biden gets in.
And a stable of establishment Democrats have made it clear, before the field is even set, that they will support Biden if he runs.
It all puts Biden in a powerful position, but it also comes with plenty of risks: By waiting, Biden is giving other Democrats time to court top staffers and donors, and the longer he waits the less patience those Democrats will have. Multiple Democratic operatives, who requested anonymity to speak openly about the former vice president, told CNN that some staffers were waiting for Biden's decision before making their own 2020 moves. Many worked in the Obama administration and have an affinity for Biden, but worry that, by waiting too long, they could be left out of 2020 if the former vice president opts not to run.
Other Democrats are further along in their 2020 planning than Biden, too. Massachusetts Sen. Elizabeth Warren has entered the race and traveled to Iowa over the weekend, while possible candidates like Sens. Cory Booker, Kamala Harris and Kirsten Gillibrand are interviewing potential aides and lining up campaign headquarters. Former Housing and Urban Development Secretary Julian Castro is expected to announce his presidential bid on Saturday in San Antonio, while candidates outside Washington, like Colorado's John Hickenlooper and South Bend, Indiana Mayor Pete Buttigieg are expected to be close behind.
Biden's team has been quietly working behind the scenes to make sure the former vice president is well positioned should he decide to pursue a bid. They have held preliminary conversations about what staffing for a possible presidential campaign would entail and fielded interest from operatives outside the existing Biden network, but have made no commitments.
Democrats considering a 2020 run who believe they would attract similar supporters to Biden -- and the top advisers who are putting the pieces in place for different presidential campaigns -- have been closely watching Biden's moves and using them to gauge their own chances.
Former New Orleans Mayor Mitch Landrieu has told allies that he would not run if Biden gets into the race. The two Democrats met in 2018, and Landrieu, who is thinking about a run but does not believe he has to announce a decision until May, according to a source close to the mayor, has been publicly complementary of Biden.
"I would like somebody that knows exactly what they're doing because they've done that before, that can stabilize and just rebalance the country for three, four years," Landrieu told CNN's David Axelrod in 2018. When the former Obama adviser said he is describing someone like Biden, Landrieu said, "I think I am."
Biden's decision has also factored into what former Virginia Gov. Terry McAuliffe will do.
A source close to McAuliffe tells CNN that Biden, more than other possible contenders, directly impacts the former Virginia governor's decision to run, but adds that McAuliffe would still consider running if Biden is in.
"It is a factor in his thought process," the source said. "They would likely be speaking to the same voters and Biden would impact his chances."
The source added: "It would certainly not rule it out, but it is a factor in his thinking."
McAuliffe, who had made hundreds of calls to donors and possible supporters since the 2018 midterms, has expressed the same to top Democrats.
Yet in an interview Monday with CNN's Kate Bolduan, he welcomed Biden into the race.
"I do think Vice President Biden is probably running, from my conservations with him," McAuliffe said, insisting his decision is not tied to Biden's. He added: "The more the merrier. It's good for democracy."
Other Democrats are even thinking about their 2020 bids as a possible compliment to Biden.
Rep. Eric Swalwell, who traveled to Iowa in December and told CNN that he is seriously considering a bid, has said that he would be open to running as Biden's running mate, should the 2020 race come to that.
"I am still taking time to make that decision," he said of running. "I love Joe Biden, but I think none of us could say we are the only people (who can beat Trump). ... I think this showcase of talent is going to be the best thing for our country."
Biden's influence is also extending beyond the large field of 2020 Democrats considering a run and into the world of establishment Democrats -- many of whom have worked with Biden -- and are eager for an elder statesman to take on Trump.
The will-he-won't-he-run speculation around Biden comes as several prominent establishment Democrats have voiced their preference for a Biden candidacy. New York Gov. Andrew Cuomo, a longtime friend of Biden, said the former vice president has the "best case" to make among the potential Democratic 2020 hopefuls. California Sen. Dianne Feinstein declared, "My candidate would be Joe Biden," even as her state colleague Sen. Kamala Harris is considering waging a presidential campaign.
Biden's two home-state senators also are on board with a Biden run.
"He'd be my first pick. My second pick would be Joe Biden. My third pick would be Joe Biden," Delaware Sen. Tom Carper told CNN. "I think that he would be the strongest candidate that we could field, and his selection of vice president as running mate would be very important."
"I think he'd make a great candidate, and I think he'd make a great president. Joe Biden has more relevant direct recent experience than anyone in my party who could run for president," Delaware Sen. Chris Coons told the News Journal. "I think he is more broadly known, better respected, and has more of a heart for America's middle class than any of the other folks who I think are going to run for the nomination in our party."