President Biden leaves the White House on Tuesday morning to travel to New England for campaign receptions. Ricky Carioti/The Washington Post

BOSTON — President Biden said Tuesday he might not be seeking a second term if former president Donald Trump had not launched his own campaign for the White House.

“If Trump wasn’t running, I’m not sure I’d be running,” Biden said at a campaign fundraiser in the Boston area. “But we cannot let him win.”

The comments punctuated a stretch that has seen Biden speaking in increasingly stark terms about the threat he says a second Trump term would pose to American democracy. The remarks also come as Biden, who turned 81 last month, has tried to downplay concerns in the Democratic Party about his age.

Polls have shown a tight race between Biden and Trump next year, an increasing source of angst for many Democrats. The Biden campaign has downplayed the polls, saying Biden will prevail once voters start focusing on the race in earnest, especially if Trump is the GOP nominee and Americans begin comparing the two nominees directly.

In the meantime, Biden has sought to frame Trump’s candidacy as an existential threat to the country. He has said Trump and what he calls “MAGA Republicans” are seeking to dismantle U.S. democracy and eliminate many of Americans’ fundamental rights.

During fundraisers in the Boston area Tuesday, the president warned of the restrictions he said Trump would place on abortion, and he emphasized the former president’s vow to repeal the Affordable Care Act.

Biden also again raised the fact that Trump has called his political enemies “vermin,” saying the comments echo the language used in Germany in the 1930s, a time when the Nazis rose to power.

“I’ve been around in politics for a while, and I never thought I’d run in an election like this,” Biden said Tuesday of what is shaping up to be a rematch of the 2020 presidential election. “This time we’re running an election denier-in-chief. Trump’s not even hiding the ball anymore.”

Biden also made light of his age during the fundraisers, as polls show many Democratic voters are deeply concerned about it.

During his first fundraiser Tuesday, Biden noted that he got 81 million votes in the 2020 election and joked, “Almost like somebody’s age. It’s hell turning 40 twice.” The president made a similar joke at a second fundraiser.

Biden’s candidacy has faced fresh questions in recent weeks as polls show that young voters – a group that was critical to his 2020 victory – disapprove of his handling of the Israel-Hamas war. Some Muslim American and Arab groups have also begun urging their communities not to support Biden in 2024. While Muslims and Arabs are not a large voter group, their votes could tip the scales in tightly contested states such as Michigan, which has a growing Arab American population.

Biden at times on Tuesday took an incredulous tone as he described Trump’s actions and comments. He noted that Trump, who continues to falsely deny that he lost the 2020 election, did not attend Biden’s inauguration, saying Trump was the first president to skip the inauguration of his successor.

“He didn’t even show up at my inauguration,” Biden said. “I can’t say I was disappointed. But he didn’t show up.”

Biden also signaled disbelief as he recounted Trump’s statement that immigrants are “poisoning the blood of our country.” He added, “What in God’s name is going on?”

Wang reported from Washington.