It was the fourth time in the past six weeks that Biden’s campaign has likened Trump’s remarks to Hitler’s in written statements and probably not the last. The president’s team has been ramping up attacks on Trump as it barrels toward a likely rematch with him, and historians say that Trump’s recent comments about immigrants — as well as those likening his political foes to “vermin” — have echoed Hitler’s words.

Biden’s more aggressive posture also underscores that threats to democracy remain at the core of his messaging push even as he tries to simultaneously persuade voters that he is best equipped to handle the economy. It’s similar to the strategy Democrats successfully employed in the 2022 midterms — and a throughline that senior campaign officials said dates back to Trump’s response to the violent white supremacist rally in Charlottesville, Va., which inspired Biden’s own presidential run.

“Every time he says it, we are going to call it out,” said Michael Tyler, the Biden campaign’s communications director. “He’s going to echo the rhetoric of Hitler and Mussolini, and we’re going to make sure that people understand just how serious that is every single time.”

The approach was informed by Biden’s meeting with a group of historians last year over what he saw as increasingly grave threats to the nation’s democracy by Trump and his supporters. The historians encouraged the president to call out his predecessor every time he evoked Hitler or other dictators.

“I think the president and his campaign have a moral obligation to highlight and condemn language that is so horribly incendiary,” said Jon Meacham, one of the historians who attended that meeting with Biden. “Authoritarianism must be challenged, and things need to be called by their name.”

Biden’s campaign did that in November, when Trump embraced Hitler’s use of the word “vermin” in a rally, also in New Hampshire.

“On a weekend when most Americans were honoring our nation’s heroes, Donald Trump parroted the autocratic language of Adolf Hitler and Benito Mussolini — two dictators many U.S. veterans gave their lives fighting,” Biden campaign spokesperson Ammar Moussa said in a statement at the time.

At a fundraiser soon after, Biden honed in on Trump’s “vermin” comments himself.

“A specific phrase with a specific meaning. It echoes language you heard in Nazi Germany in the ’30s,” he said. “And it isn’t even the first time. Trump also recently talked about, quote, ‘the blood of America is being poisoned’ — ‘the blood of America is being poisoned.’ Again, echoes the same phrases used in Nazi Germany.”

The strategy is not without risks. As one Biden campaign aide acknowledged, some voters may view the comparisons as an over-the-top escalation.

But the person, who was granted anonymity to speak about the campaign’s internal thinking, said that Trump is explicitly laying out the autocratic ways in which he will govern in a second term and the stakes must be made clear.

“We’re in unprecedented territory in a very, very negative, negative way,” said former Sen. Ted Kaufman (D-Del.), a longtime adviser to Biden, who recalled Trump’s remarks after the Charlottesville rally. “It’s ironic almost that the issue that put Biden over the top in deciding to run against Trump has now been topped.”

Meacham also said he “worried that too many Americans may become inured to” the rhetoric. “That’s among the reasons disasters have happened elsewhere in the past. Let’s be clear: This isn’t an ordinary time. Trump is not saying ordinary things.”

Trump has long praised dictators and used racist and anti-immigrant language. In recent months, he has doubled down. When Fox News host Sean Hannity tried to push him at a town hall this month to say he wouldn’t abuse his power, Trump said he wouldn’t be a dictator “except for Day One.”

Trump has also vowed to appoint a special prosecutor to “go after” Biden and his family. He is planning a widespread immigration crackdown and wants to exert more authority over the federal bureaucracy.

The Trump campaign did not respond to a request for comment.

Celinda Lake, a pollster for Biden’s 2020 campaign, said that earlier this year, she was concerned voters might not take seriously the threat that another Trump presidency poses. In focus groups at the time, she said, voters remarked that, though Trump sometimes “speaks without thinking,” his time in office “wasn’t a disaster.”

As Trump’s language has grown more severe in the last month, however, that has changed.

“We’re seeing in focus groups many more people comment that he’s too divisive, that ‘I don’t like his temperament,’ that ‘I don’t like his personality.’ It’s really starting to come back,” Lake said. “He’s gone too far.”

Jim Messina, who led Barack Obama’s reelection campaign in 2012, also said it’s important for the Biden campaign to stress “that this guy is even crazier than he used to be — and it takes a long time to get that through.”

“I’m not worried about [voters] hearing about this stuff too much,” he said. “I’m worried … if you don’t call him on it that it becomes normative.”

Biden campaign aides said that this is not merely a debate about language, and they are intent on showing voters what a more autocratic second term of Trump would mean for their own rights.

To help make that case, the campaign launched a TV advertisement last week, in both Spanish and English, that likened Trump to Latin American strongmen. In the spots, images of Trump flash alongside those of Hugo Chavez and Nicolas Maduro as a narrator says that Republicans, “like dictators, want to take things away — our health insurance, our rights and freedoms, and even our safety.”