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, 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 also has no plans to endorse a candidate.

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 mind-set and strategy of Democratic 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 such leading contenders as Harris, Booker and Sen. Elizabeth Warren; underdogs like Pete Buttigieg, mayor of South Bend, Ind., and prominent figures who remain undecided, like Eric Holder, his former attorney general, and former New York Mayor Michael Bloomberg.

During these informal conversations, 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 win, these people said, even after years of clashing with the forces of right-wing populism. 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 GOP-leaning areas, courting rural voters and other communities that tend to distrust Democrats.

Obama senior adviser Eric Schultz 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.”

He has indicated 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.

Democrats have kept the meetings almost entirely confidential.