WASHINGTON >> Barack Obama had a plan of sorts for the 2020 presidential primaries, according to several allies and advisers: Stay out of the way, offer advice when asked, promote voting rights, finish a new memoir — then jump back into politics after Democrats picked their nominee.

Things haven’t worked out like that.

After three years of largely steering clear of divisive internal Democratic fights, Obama is increasingly moving off the political sidelines and trying to play a new role: elder statesman for a party grappling with its post-Obama identity. Associates describe a former president impelled by his belief that the diverse electorate he once unified is being split by “Medicare for All” and immigration proposals — ideas that he thinks could alienate moderate voters in the 2020 election.

From appearances before party donors to conversations with activists and lawmakers, Obama is going public with a message for his fellow Democrats he had previously made in private to allies and a handful of friendly journalists: Focus on defeating President Donald Trump, ditch the ideological purity and the “cancel” culture, or face the abyss.

He is expected to amplify these concerns about the 2020 race Thursday at an event with party donors in San Francisco, an aide said, giving him a fresh chance to reflect on tonight’s Democratic debate in Atlanta. (Several of those interviewed for this article spoke on condition of anonymity to describe his private views.)

“What’s happening is, he’s seeing the campaign move to a different stage, and he’s reacting to it,” said David Axelrod, a longtime Obama adviser. “He sees himself as a ref, not a player. What he’s saying is, ‘Hey, let’s not put so much passion into the intramurals that we forget to show up for the actual game.’”

Obama made that point in the bluntest possible terms last week to an audience of Democratic donors who had expected him to offer reassurances about the strength of the Democratic field and the durability of the party’s leading moderate, former Vice President Joe Biden.

After praising the field and suggesting any of them could defeat Trump, he issued a warning that appeared aimed at Sens. Elizabeth Warren and Bernie Sanders, the two leading liberals in the 2020 race, who have proposed far-reaching changes to the U.S. economy and health care and education systems.

“The average American doesn’t think that we have to completely tear down the system and remake it,” said Obama, appearing onstage at the annual meeting of the progressive Democracy Alliance in Washington with Stacey Abrams, the former Georgia candidate for governor. “There are a lot of persuadable voters, and there are a lot of Democrats out there who, they just want to see things make sense. They just don’t want to see crazy stuff.”

Obama voiced similar concerns two weeks earlier, calling on young Democrats to move past “woke” culture, which he sees as an impediment to creating a coalition that includes moderates, independents and Republicans who don’t share their opinions on some issues. “That’s not activism,” he said during an event for the Obama Foundation in Chicago — a comment that was disparaged by some critics as paternalistic. “That’s not bringing about change.”

Obama is hardly undertaking a full-on intervention, and modulating criticism with statements of reassurance: He is not calling out Democrats by name, and by all accounts, he has chosen not to get involved behind the scenes in playing favorites among the candidates.

Yet Obama, who foreshadowed his public warnings in a closed-door pep talk for newly elected House Democrats last spring, is clearly trying to make the case for a moderate and inclusive brand of politics — a message that helped him win in traditionally Republican states like Indiana and North Carolina in 2008. It is a viewpoint reflected in findings by a recent New York Times/Siena College poll of six battleground states showing that Democratic primary voters prefer candidates who pursue moderate, as opposed to liberal, policy goals.

“He’s trying to set a tone,” said Robert Wolf, a friend of Obama and former chairman of UBS Americas, a part of the global investment firm. “He cares first about electability; whatever is second is a very distant second.”

Obama’s coming remarks Thursday will be part of an onstage interview with Thomas Perez, Democratic National Committee chairman, at a fundraising event in California. He has no plans to speak about the 2020 race for the rest of the year, according to the Obama aide who described his plans for Thursday.

The former president’s comments also reflect his own policy legacy, which has come in for modest questioning and criticism at times by some Democrats in the debates and on the campaign trail. (One friend said Obama had brushed off debate criticisms, joking that the eventual winner will “come back to me when they need me.”)

Obama was initially reluctant to attack Trump after he left the Oval Office, in part because he wanted to embrace the informal practice adopted by his predecessor, George W. Bush, of not attacking a presidential successor, former aides said. But he was also concerned that going after Trump would play into Republicans’ hands by prompting a backlash, they added.

By the 2018 midterms, Obama abandoned that reticence and campaigned aggressively against Trump, emboldened by the president’s halfhearted response to his attacks.

He also offered vague praise for the large-scale health care policy that Sanders and Warren are now championing. “Democrats aren’t just running on good old ideas like a higher minimum wage, but they’re running on new ideas like ‘Medicare for All,’” he said in a speech at the University of Illinois in September 2018.

The big difference now is Obama’s willingness to publicly criticize others in his party, however indirectly, something he had avoided.

Katie Hill, a spokeswoman for Obama, said that he was not targeting Sanders or Warren in his remarks last week and that his public declarations in support of the Democratic field and a diversity of opinions are the core of his message.

“Since leaving office, President Obama has worked to stay out of the political fray, in part to let other, new voices in the Democratic Party rise up,” Hill said Wednesday. “Just like in 2018, he’ll be out on the campaign trail next fall working hard for whoever our nominee is.”

But Obama made it clear in his remarks to the Democracy Alliance that he sees the Medicare for All plan as a threat to the party among moderate voters, many of whom fear they will lose their private health coverage — giving them an excuse to support Trump in 2020.

Sanders, responding to Obama’s remarks last weekend, said: “I’m not tearing down the system. We’re fighting for justice.” Warren did not push back and said she was “grateful” for Obama’s passage of the Affordable Care Act. But some on the party’s left, including Rep. Ilhan Omar, D-Minn., were less accommodating, tweeting out the hashtag “#TooFarLeft” in disapproval.

Obama has also quietly expressed concerns, as have many other Democrats, about the performance of his former vice president, Biden, especially in the debates, according to two Democrats with knowledge of the interactions.

His unfinished book, a memoir spanning his eight years in office, is also weighing heavily on Obama, who sees it as his principal legacy project, a literary bookend to his highly regarded 1995 autobiography “Dreams From My Father.”

The former president, a meticulous writer and chronic procrastinator, has blown through several self-imposed deadlines — he told Abrams it was “a pain” — and no one quite knows when it will be finished, according to two people with knowledge of the situation.

The process of reliving his presidency day by day, writing in longhand and revising it with his speechwriter Cody Keenan, has put him in a reflective and, at times, feisty mood, associates said, making him more willing to express his thoughts to a wider audience.

Obama has taken great care not to express his opinions about particular candidates — at least in earshot of anyone who will leak them — and has told people around him that he wants to avoid even the slightest perception that he is “thumbing the scale” for any candidate as he did by tacitly backing Hillary Clinton’s primary campaign in 2016.

He has, nonetheless, offered personal support to Biden but has been careful to cast his efforts in personal, not political, terms. Earlier this year, he described his motivation, telling Biden’s brain trust that he did not want to see Biden “embarrass himself.”

Obama’s relationship with Warren and Sanders has been more distant but cordial. Both reached out to Obama shortly after they announced their candidacies earlier this year, and he offered each a bit of individualized advice, counseling Sanders to espouse “mainstream” ideas, a person close to the Vermont senator said. He urged Warren to embrace party “unity,” according to two people close to the Massachusetts senator.

He has a deeper connection to former Gov. Deval Patrick of Massachusetts, a close friend who has served on his foundation’s board, and discussed the possibility of a campaign with Patrick last year, people close to both men said. But he now believes Patrick’s entrance into the race last week came too late, these people said.

Obama is acutely aware of timing when it comes to his own actions. His appearance at the conference was intended to reassure nervous donors that he had confidence in the ultimate outcome of the 2020 election. He added his warning to an outline of his remarks only a few days before the conference, a person involved in the planning said.

“There are a lot of people who have been wanting him to get out there and mix it up more with Trump,” said Gara LaMarche, president of the Democracy Alliance. “People miss his voice. Even people in the room who didn’t necessarily agree with what he had to say were happy to have him back in the fray.”