By Lisa Lerer and Reid J. Epstein | New York Times

WASHINGTON — When a reporter asked former Vice President Joseph R. Biden Jr. on Saturday if he had spoken to his son Hunter about his work in Ukraine, Mr. Biden jabbed his finger repeatedly at the reporter and shot back: “Ask the right questions.”

A few hours later, when coverage of President Trump’s phone call to Ukraine’s president about Mr. Biden and his son had reached a fever pitch, the Biden campaign emailed the news media to declare — in bold underlined words — that any story would be “misleading” if it did not state upfront that Mr. Trump’s claims were unsubstantiated.

On Sunday night, the Biden campaign released a fund-raising appeal on Twitter asking, “Will media see through Trump’s sleazy playbook? Or fall for it again?” And by Tuesday, the drumbeat of warnings to the press had grown so intense that even Lanny Davis, a longtime Democratic operative, weighed in, attacking “innuendo journalism.”

For the past three years, every Democratic campaign, politician and activist has operated in the shadow of Hillary Clinton’s 2016 loss, caught in a cycle of self-recrimination and soul-searching about how to defend themselves against Mr. Trump and his Republican allies in 2020. It’s a conversation that began in the hours after Mrs. Clinton’s unexpected loss, as aides reckoned with their inability to defend her from Mr. Trump’s conspiratorial accusations, and has continued ever since, with Mrs. Clinton herself dispensing advice in private conversations with Democratic primary candidates as they prepared to begin their campaigns.

Now, Mr. Biden and his team think they have the answers. Among their conclusions: There are no guardrails. No one else will fight your battles. Responding to accusations from Mr. Trump and his allies — even to deny them — only gives them oxygen. And haranguing the referees in the media is a must.

Former Senator Bill Nelson of Florida, who has endorsed Mr. Biden, has advanced the campaign’s argument that the news media has a unique responsibility to provide the proper context for accusations being tossed around in the political arena — a duty he and other Biden backers say they failed to do in 2016.

“In the old days when the truth was something that was respected and the press could be a source of the truth, that was one thing,” said Mr. Nelson. “Now when you have a player on the political stage that will say anything and has been shown to not tell the truth over and over and over, freedom of the press means that there is a new responsibility of the press.”

Former Gov. Terry McAuliffe of Virginia, a Democrat who is unaligned in the primary, was even blunter: “The coverage of the emails was ridiculous,” he said. “It gave Biden license to come out and say, ‘Are you kidding me? We’re not going through this again.’”

Frank Sesno, a former broadcast journalist and the director of the School of Media and Public Affairs at George Washington University, said ignoring questions about Hunter Biden altogether would be irresponsible journalism. “I have not seen egregious, irresponsible reporting at all,” he said, adding, “When the president of the United States says something publicly, you can’t make that go away and no responsible news organization is going to ignore it.”

Senior aides on the Biden campaign argue that the Clinton campaign was not forceful enough in responding to the long drip of stories about her use of a private email server and the Clintons’ family foundation. Those news reports, they argue, only helped to feed Mr. Trump’s narrative that his rival was an untrustworthy creature of Washington.

Rather than litigate the specifics in public, Biden aides and allies argue that Mrs. Clinton and her team should have focused more on privately shaming the media out of investigating allegations, while leaving Mrs. Clinton focused on attacking Mr. Trump and delivering her own message to voters. The allies spoke on condition of anonymity to disclose conversations about campaign strategy.

“Democrats are very wary of a candidate being Hillary-ed going into 2020,” said Zac Petkanas, the director of rapid response for Clinton’s 2016 campaign.

Karen Finney, a former Clinton campaign spokeswoman who is unaligned in the 2020 race, said Democrats “spent a lot more time talking about Hillary Clinton’s emails than we should have, given some of the more glaringly troubling actions of Trump.”

Unlike Mrs. Clinton, Mr. Biden is unlikely to ever spend time diving into the details of the allegations, aides say, fearing that doing so would allow Mr. Trump’s allegations to further hijack the national political conversation.

Former Iowa Gov. Tom Vilsack, who hosted a Biden campaign in his front yard but has yet to endorse any candidate for president, said, “He understands that you can’t let something like this go.”

“But you have to be thoughtful about how you respond to it so that you don’t let the president, with all of his capacity to impact folks like you to write what he says every day, to control the complete narrative,” he added.

Mr. Biden’s team is learning lessons from 2016. Among them: No one else will fight your battles. Mark Makela for The New York Times

Throughout the 2020 race, Mr. Biden has pitched himself as the strongest candidate to combat Mr. Trump’s attacks. Whether combating Mr. Trump through the mainstream media proves correct will provide voters with a critical, real-time test of his strength, as allegations that Mr. Trump pressured the president of Ukraine to open a corruption investigation of Mr. Biden and his son Hunter are at the heart of a political firestorm that prompted Democrats on Tuesday to begin impeachment proceedings.

Mr. Biden’s rivals, too, are watching closely: While they have responded to the developments on Ukraine by denouncing Mr. Trump’s actions, several camps are privately gaming out how they would handle a similar onslaught from the president and his allies.

“We’ve got to remember that they’ll either find a vulnerability or they’ll invent one for everybody,” Mayor Pete Buttigieg of South Bend, Ind., told reporters traveling on his campaign bus.

But even some opponents privately worry that this moment could elevate Mr. Biden’s campaign if he handles it deftly, putting the former vice president on equal footing with the president and making it hard for his rivals to get their share of attention.

“Trump’s lost it and he’s terrified of Biden, and Biden’s not going to take any of his guff at all,” said Mr. McAuliffe. “This is actually good for Joe Biden. It puts him right at the forefront.”

There is no evidence so far to support Mr. Trump’s claim that Mr. Biden improperly intervened to help his son’s business in Ukraine. But that hasn’t stopped the Trump campaign from pushing the allegations, giving Mr. Biden the nickname “Quid Pro Joe.” (Mr. Trump himself seems to be sticking with “Sleepy Joe.”)

During a fund-raiser in Baltimore on Tuesday night, Mr. Biden fired back with a moniker of his own: “He loves nicknames. I’d like to give him a new nickname — former President Trump.”

Democrats in 2016 “spent a lot more time talking about Hillary Clinton’s emails than we should have,”
said one of her former staff members. Doug Mills/The New York Times

Keeping the focus on beating Mr. Trump is an approach Mr. Biden has held since the final weeks of the 2016 campaign, when he urged the Clinton team during his weekly meetings with her staff to avoid debating topics like the “Access Hollywood” tape.

“I said, ‘I respectfully recommend she stand there and say, everybody knows who Donald Trump is, let me tell you what I’m going to do for the country,’ and not get into the debate, because it just drags it down,” Mr. Biden told voters in New Hampshire earlier this month.

The stories about Mrs. Clinton’s email server and family foundation fed into an already existing narrative of corruption that Republicans had been pushing for decades; that is a challenge Mr. Biden does not face. For decades, he was consistently ranked one of the least wealthy members of the Senate.

The allegations against Mr. Trump — that he used the power of his office to influence a foreign government to help him politically — are also far more serious than during the 2016 race.

“Biden doesn’t have to answer for nothing,” said James Carville, the Democratic strategist and longtime adviser to the Clintons. “There’s one story here. The president of the United States tried to sic a foreign government on a political opponent.”