A secret meeting of former President Barack Obama’s financial backers convened in Washington early this month: Organized by David Jacobson and John Phillips, Obama’s former ambassadors to Canada and Italy, the group interviewed an array of 2020 presidential candidates and debated whether to throw their wealth behind one or two of them.

Obama had no role in the event, but it unfolded in his political shadow: As presidential hopefuls like Sens. Kamala Harris, Cory Booker, Amy Klobuchar and Sherrod Brown auditioned before them, the donors wondered aloud whether Obama might signal a preference in the race, according to three people briefed on the meeting, who spoke on condition of anonymity.

David Axelrod, Obama’s former chief strategist, told the group they should expect no such directive. Axelrod confirmed in an interview that he briefed the gathering, recalling: “They asked me about Obama endorsing. I said, ‘I don’t imagine he will.’”

Axelrod said he had been sharing his own perspective, not speaking as an official Obama emissary. But his forecast matches what Obama has told friends and likely presidential candidates in private: that he does not see it as his role to settle the 2020 nomination, and prefers to let the primary unfold as a contest of ideas. Michelle Obama, the former first lady, also has no plans to endorse a candidate, a person familiar with her thinking said.

Even former Vice President Joe Biden does not expect to secure Barack Obama’s backing if he runs, according to allies of Biden’s.

Yet if Obama has all but officially taken a vow of neutrality, he remains the party’s most convincing model for success at the national level, and continues to shape the mindset and strategy of Democratic presidential candidates.

He has counseled more than a dozen declared or likely candidates on what he believes it will take to beat President Donald Trump, holding private talks with leading contenders like Harris, Booker and Sen. Elizabeth Warren; underdogs like Pete Buttigieg, mayor of South Bend, Indiana; and prominent figures who remain undecided on the race, like Eric Holder, his former attorney general, and Michael Bloomberg, the former mayor of New York.

During these informal conversations, usually at his office in Washington, Obama has offered a combination of supportive advice and sober warnings, cautioning candidates that running for president is a more punishing process than they could ever imagine, according to seven people who have spoken with him directly or were briefed in detail on the meetings.

Obama continues to express frustration that he did not anticipate Trump’s victory, these people said, even after years of clashing with the forces of right-wing populism as president. He has urged candidates to push back on Trump’s bleak and divisive rhetoric about economic change, and to deliver a competing message that can resonate even in Republican-leaning areas, courting rural voters and other communities that tend to distrust Democrats.

Eric Schultz, a senior adviser to Obama, said the former president was encouraged by the “diverse, experienced and principled” field of candidates taking shape, and said Obama had been “happy to speak privately with candidates seeking his guidance on the best way to lead the country.”

“President Obama counsels candidates to always show up and make their case even in areas or in front of audiences they may not necessarily win; express views and positions that reflect their genuine beliefs; and share a positive vision for the country true to their own personal story,” he said.

The discreet role Obama is taking reflects his long-standing ambivalence about acting as a partisan political leader, and has the potential to disappoint Democrats who pine for him to intercede more decisively. Known for his lack of interest in intraparty wrangling when he was president, Obama has privately voiced both an impatience to move on from politics and an urgent sense of responsibility to do what he can to thwart Trump.

Some Democrats still hope Obama might help resolve the primary in an active way, perhaps if the contest narrows to just two candidates and he believes one of them cannot beat Trump. Steve Westly, a California investor who was a major fundraiser for Obama, said he expected the race to “come down to two or three candidates very quickly” and foresaw an opening for Obama to act.

“I am sure he feels, as an American, that he wants to make sure the Democratic Party puts up the best possible candidate,” Westly said.

Obama has indicated to candidates that he worries about the possibility of a damaging primary fight, and has urged them to avoid attacking each other in bitterly personal terms that could help Trump. He has also hinted that he sees a relatively open space for a more moderate Democrat, given the abundance of hard-charging liberals in the race.

Democrats have kept the meetings almost entirely confidential, out of deference to Obama. Beto O’Rourke, the former Texas Senate candidate, briefly described his session with the former president in an interview with Oprah Winfrey this month, recalling that Obama spoke with disarming candor about the personal strain of running for president. O’Rourke said Obama had not lobbied him to run.

“You asked if he encouraged me to; he did not,” O’Rourke said. “But he was very generous in sharing what his thought process was, leading up to that decision.”

Other candidates have declined to share details of their meetings with Obama, but invoke him reverently on the campaign trail. Booker drew laughter and applause from a crowd in Cedar Rapids, Iowa, last weekend, when he declared: “I miss Obama — and I miss her husband, too!”

The primary will represent something of a test for Obama’s brand of politics, if perhaps not of his influence within the party. He is personally revered by many Democrats, and his achievements like the Affordable Care Act, the Paris climate agreement and the regulations he imposed on banks and coal companies are seen as sacrosanct by most liberals.

But Obama’s party has also plainly moved leftward on core matters of policy since his term ended, and some factions have grown contemptuous of the consensus-seeking approach Obama took as president. The coming primary campaign may hinge in part on whether Democratic voters favor making gradual improvements to Obama’s legacy or pursuing more disruptive policy changes like enacting single-payer health care.

Obama’s doctrine of nonintervention could represent a setback, though not an unexpected one, to Biden. The former vice president and his political allies have confided to potential supporters that they do not expect Obama to issue an endorsement in the primary, for Biden or anyone else.

But the two men have discussed the race, and allies of Biden hope Obama might speak favorably about Biden’s service as his running mate and vice president, people who have spoken to Biden’s inner circle said.

Bill Russo, a spokesman for Biden, declined to comment.

In public and private, Obama has spoken admiringly about a few potential presidential candidates as they burst upon the national scene, applauding signs that a newer generation of leaders is rising in the party. He has told friends that O’Rourke and Buttigieg represent precisely that kind of generational change, and expressed deep admiration for Mitch Landrieu, the former mayor of New Orleans, for his approach to removing Confederate statues in his city.

After campaigning in Georgia last fall, Obama described Stacey Abrams, the party’s nominee for governor in 2018, as one of the most impressive candidates he had encountered.

And Obama took a keen interest in Deval Patrick, the former governor of Massachusetts, when he was considering a presidential run last year. A former civil rights lawyer with moderate instincts, Patrick spoke repeatedly with Obama before announcing in December that he would not run, citing the strain a campaign would impose on his family.

Obama has spoken out selectively since leaving office, usually focusing on themes related to the integrity of the political system. He campaigned widely in the midterm elections, focusing many of his endorsements on promoting women and candidates of color, and he has taken a leading role in a group set up to fight congressional gerrymandering, the National Democratic Redistricting Committee. Obama is expected to help raise money in the coming months for the organization, said a spokesman for the group, which is helmed by Holder.

To some veteran Obama supporters, there is a certain irony to Democrats wishing that Obama would act as an old-school party leader and decree his preferences from on high.

Rufus Gifford, a top Obama fundraiser who served as ambassador to Denmark, suggested that the diversity of the Democratic candidates was a consequence of Obama’s path-breaking presidency. He said the 2020 field was a tribute to the former president, even if it left voters and donors struggling to parse their options.

“You look at the number of women, the racial diversity, the diversity of experience, the different levels of public service — I think a lot of that can and should be attributed to the legacy of Barack Obama,” Gifford said.