Well before most candidates will announce they are running and publicly plead for support from voters, as many as 20 prospective Democratic candidates are taking steps that could lay the financial foundation for a campaign, even if actually running turns out to be only a transitory thought.
They are making their cases to wealthy donors, while spending briskly through political committees to pay staff members, organize fund-raisers, arrange travel and rally small donors and volunteers, according to campaign finance reports filed with the Federal Election Commission, the Internal Revenue Service and state regulators.
Before any run for president, many prospective candidates are facing 2018 re-election campaigns of their own. But in several cases, they are not expected to face serious challenges, and their re-election campaigns are being watched closely by donors and other party insiders to assess their viability for 2020. In much the same way, Hillary Clinton used her Senate re-election campaign in New York in 2006 to build a staff and national fund-raising operation that became the foundation for her unsuccessful 2008 campaign for the Democratic nomination.
Mrs. Clinton’s successor in the Senate, Kirsten E. Gillibrand, has paid more than $1 million this year through her political committees to a top online fund-raising firm, which has helped her reap $2.3 million this year in small donations for a 2018 re-election race in which she is the heavy favorite. She has also continued courting major donors, holding two fund-raisers last month in the Hamptons. At one, she was asked by a donor whether she was considering running for president. She said she was focused on 2018, but did not explicitly rule out a White House run, according to an attendee.
Gov. Terry McAuliffe of Virginia, a former chairman of the Democratic National Committee who maintains deep ties to some of the party’s most generous donors, has spent $164,000 through his political committee on staff members and consultants this year, and $46,000 in recent months to hold fund-raisers and other events at a Washington steakhouse. The PAC, which rents office space in Washington, this year collected big checks from longtime backers of the Clintons, including $50,000 from Howard Kessler, a Boston financier, and $25,000 each from the Virginia real estate developer Albert J. Dwoskin and from Douglas J. Band, a former Clinton aide and fund-raiser. The PAC has also donated more than $315,000 to Democratic candidates and committees in Virginia this year.
Mr. McAuliffe — who is barred by term limits from running in the Virginia governor’s race this year — said during an appearance Sunday on CNN that he got asked “all the time” whether he was running for president. “We’ll see what happens down the road. But I have no intentions of running for president,” he said, explaining that his focus was on finishing his governorship and helping the party’s gubernatorial candidates in 2018.
Aides to Ms. Gillibrand and those of other prospective candidates contacted for this article similarly insisted that their fund-raising had nothing to do with setting the stage for 2020.
It is considered bad form to start running for president — or even to unofficially explore the possibility — before the preceding midterm election. That is partly because presidential campaigns can divert valuable funds away from important down-ballot races for which it is more difficult to raise money.
There are also tactical advantages to waiting, including keeping open the possibility of remaining in Congress in states that bar members from seeking re-election while also running for another office. And campaign finance regulations limit the types and amounts of money that declared presidential candidates can raise, while politicians who have not declared for the presidency can continue accepting larger contributions to a range of political committees, including state-level committees like the one used by Mr. McAuliffe.
Major donors figure to play an outsize role in the 2020 Democratic race, which will be the first with neither an incumbent nor a candidate who is a clear donor favorite since the Supreme Court’s 2010 Citizens United decision. That ruling paved the way for outside groups technically independent from the campaigns, including those known as super PACs, to raise unlimited sums from wealthy donors and corporations to support or oppose candidates.
But there also are early indications that the courtship of the party’s donor class could in itself become an issue the way it did in 2016, when Senator Bernie Sanders of Vermont did little high-dollar fund-raising. Relying instead on a historic surge in small donations brought in by a sophisticated online fund-raising operation, Mr. Sanders charged that Mrs. Clinton was insufficiently supportive of liberal proposals like publicly funded education and health care because she was beholden to special interests and big donors.
Mr. Sanders is still at it, crisscrossing the country stumping for populist candidates and causes. A political organization founded by his former campaign aides has raised nearly $5.3 million in the past year from donations that average $22. And, even as he faces his own 2018 re-election race in Vermont, his backers are signaling that they will support another presidential run.
Senator Elizabeth Warren of Massachusetts, whose populist rhetoric has attracted a grass-roots activist and donor base that overlaps with Mr. Sanders’s, has said that the party should avoid a temptation to moderate its views, and that its candidates should not “grovel on Wall Street” to raise money.
Ms. Warren has built a formidable online fund-raising operation, which has brought in $5.1 million this year for her 2018 re-election campaign and allowed her political action committee to donate $270,000 to other Democrats. Yet she also has joined a parade of would-be Democratic presidential contenders who have paid visits to the wealthy summer enclaves that serve as A.T.M.s for the party’s candidates.
“I think Elizabeth is laying the groundwork for a run. She won’t admit it, but it looks like that,” said Guy Saperstein, a San Francisco lawyer and part owner of the Oakland Athletics. Mr. Saperstein, who tried to coax Ms. Warren into the 2016 presidential race with an offer of a $1 million super PAC contribution, met with her in June in San Francisco.
“Why would she be out in California if she wasn’t interested in running for president?” Mr. Saperstein said. “I mean, she says she’s raising money for her re-election, but she won’t have any problems with that.”
So far, only Representative John Delaney of Maryland has said he will be a candidate for the Democratic nomination for president, announcing that he will not run for re-election in order to wage a long-shot campaign. He said in an interview that he was willing to underwrite his campaign from a personal banking fortune estimated at $90 million, but that he was working to raise money from a mix of small and large donors.
“The role of the big donor, if you will, is less than it used to be,” Mr. Delaney said. “Any candidate running for president in 2020 needs to have a comprehensive strategy for running a well-funded campaign.”
Ms. Harris’s political action committee is paying the consulting firm that powered Mr. Sanders’s small-dollar juggernaut. And she has also worked to expand her big-donor network beyond her base in California, where she attended a fund-raiser at the home of the Hollywood agent Michael Kives on Monday night that raised more than $100,000 for her PAC. The donors in attendance, who were mostly from the Los Angeles area, seemed to be in agreement that their home-state senator would make a strong presidential candidate, even though Ms. Harris avoided the topic, according to one person who was at the dinner.
Ms. Harris also did a fund-raising swing through the Hamptons in July, and one through Martha’s Vineyard last month. On Martha’s Vineyard, she was feted at a dinner at the home of Richard L. Friedman, a Boston real estate developer, and at a fund-raiser hosted by Broderick D. Johnson, an official in the Obama White House, and his wife, Michele Norris, the author and journalist.
“There were people there who may have a view about her and 2020, but we hosted the fund-raiser because we have admired Kamala for years, and we applaud her efforts to support House and Senate Democratic candidates in the 2018 midterm elections,” Mr. Johnson said.
Ms. Harris is not up for re-election until 2022. Her political committee has donated $130,000 this year to Democratic candidates and committees, and she has raised additional money for other Democrats. Lily Adams, a spokeswoman for Ms. Harris, said the senator’s “sole priorities are fighting for Californians and electing and re-electing Democrats to the House and Senate.”
Mr. Biden, who already has deep ties to major Democratic donors, has been reaching out through his staff to arrange one-on-one meetings with some of the top donors in the party, according to donors who have been invited to meet with him.
Mr. Biden’s new political committee, American Possibilities, paid $47,000 to Blue State Digital, the firm that spearheaded the pioneering digital outreach and fund-raising for his two campaigns as President Barack Obama’s running mate. Blue State will perform similar functions for American Possibilities, which is expected to fund Mr. Biden’s political travels and donations.
Mr. Biden also met privately in May with leaders of nine new or emerging groups opposing Mr. Trump and Republicans on various fronts, and supporting Latino, African-American and millennial candidates and causes.
“He is thinking about how he plays in this moment as a former vice president,” said Quentin T. James, the founder of a group called the Collective PAC that supports African-American candidates, who was at the meeting. “I do think he has a desire to get back out there politically. If that means 2020, I don’t know.”