On the campaign trail, former Vice President Joe Biden has spoken openly and angrily about the attacks the right has waged on his family over their dealings in Ukraine, pointing to them as a sign that they consider him a threat to President Trump’s re-election.

“I wonder why they spend so much time trying to keep me from being the nominee,” Biden said at a rally in Nashua, New Hampshire, earlier this week, mentioning the millions of dollars in ads launched to try and tear down his candidacy. “Have you ever seen another party spend as much time deciding who the other party’s nominee shouldn’t be?”

There is no evidence that Biden or his son, Hunter, did anything wrong when the younger Biden was put on the board of energy company Burisma — in fact, the claims made by the White House and its allies have been effectively debunked.

And at the Democratic debate in New Hampshire, even one of Biden’s 2020 rivals, former mayor Pete Buttigieg, rejected the idea there is a “danger” in nominating Biden given the questions about his son’s dealings in Ukraine.

“No. And we're not going to let them change the subject,” Buttigieg said. “This is not about Hunter Biden or Vice President Biden or any Biden. This is about an abuse of power by the president... Look, the vice president and I and all of us are competing but we've got to draw a line here.”

“ I think there's going to be too much baggage there. I think Trump's gonna make everything up and run with it and play it just like he did Hillary. ” — Terri Gilbert

But for some Democratic voters, the damage of conspiracy theories circulated by Trump and his allies has already been done. And while certainly not the first issue voters raised, for some still rattled by the 2016 race any hint of wrongdoing—true or not—is enough to make them look elsewhere.

“I think there's going to be too much baggage there,” said Terri Gilbert, 54, a surgical technician from Newton, Iowa. “I think Trump's gonna make everything up and run with it and play it just like he did Hillary.”

At a rally for Buttigieg in Waterloo, Iowa, Maureen O’Connor, 61, a part-time retail worker, had the same concern.

“I think they are gonna dig something up on Joe before the whole thing happens,” she said. “Joe is a good candidate... I don't think we're gonna give Joe a chance.”

Rival campaigns have also noticed and, according to one Democratic operative with knowledge of the strategies, some have included a question about Biden and the Ukraine issue in their internal polling.

“It’s a real vulnerability, everyone knows that,” the operative said, adding, however, that at least with Biden Democrats know what the attack is going to be as opposed to what may be looming for the yet-to-be vetted candidates.

“It’s the devil you know or the devil you don’t know,” the operative said.

It is true that the other candidates in the race could also be weighed down by baggage once their records come into sharp relief. The Trump campaign is already planning to take advantage of Sen. Bernie Sanders’ (I-VT) self identification as a socialist, and new problematic comments made by the longtime politician have begun to surface as Sanders rises in the race. Sanders came under fire for those very views at Friday’s debate.

Still, none have gotten the attention from the GOP that Biden has in the run up to 2020.

“I wonder if the Hunter Biden stuff spooked some voters,” said David Axelrod, Barack Obama’s former chief political campaign strategist. “They're worried he is going to be Benghazi-ed."

“The biggest defining force in this primary is Democrats’ ferocious recognition of the threat that Donald Trump is to our country and to who we are as a people. And Donald Trump is so terrified of Joe Biden that he got himself impeached by trying to spread lies about him,” spokesman Andrew Bates told The Daily Beast. “Any ‘Democrat’ who traffics in Trump’s repulsive and comprehensively disproven smears will find themselves eviscerated — by more than just one campaign."

Biden, himself, has been defensive when the issue has been raised on the campaign trail.

In early December at a stop in New Hampton, Iowa, Biden called out a voter who incorrectly said Biden sent his “son over there to get a job and work for a gas company that he had no experience with gas or nothing in order to get access for the president.”

Biden responded by calling the man a “damned liar,” suggested they take an “IQ test” and appeared to call the man “fat” (the Biden campaign said the former vice president was saying “facts.)

In an interview with NBC’s Savannah Gutherie the night before the Iowa Caucuses, Biden was asked about how the impeachment trial had ensured that his son’s position on the Burisma board was in the public eye.

“No one has found anything wrong with his dealings in Ukraine, except they say it sets a bad image,” he said.

Asked whether it was “wrong” for his son to take a position on the board of a company offered to him in exchange for access to the then-sitting vice president, Biden shot back, “That’s not true, you are saying things you do not know what you are talking about. No one said that. Who said that?”

After Gutherie explained that is how the situation appeared, whether or not it was true, Biden said of his son, “ He said he regretted having done it. Speak for himself. He's a grown man.”

With the impeachment trial in the rearview mirror, the Trump campaign and its supporters are doing their best to keep the issue alive.

“ On my end of things, the Hunter thing means nothing to me. It doesn’t bother me at all. It’s just another Trump attack that he wants people to look at instead of what he’s doing. ” — Chase Denamur, Democratic voter

Just feet away from the Concord site where Democratic contenders held a town hall discussing climate change with young voters this week, a large projector affixed on the side of a parked black truck played a scene on repeat discussing Joe Biden and his son Hunter, along with other contenders. The short segment, presented by the Committee to Defend the President, a pro-Trump PAC, showed clips from various opinion programs suggesting Hunter Biden is a corrupt individual. A banner on one segment read “HUNTER BIDEN'S FOREIGN DEALS” in all caps, with a video of the former vice president. “Did Joe Biden’s son profit off father’s position as vice president?”

In New Hampshire, Democrats interviewed by The Daily Beast were less bothered by Trump’s allegations.

“On my end of things, the Hunter thing means nothing to me,” said Chase Denamur, a Democrat from Litchfield, New Hampshire. “It doesn’t bother me at all. It’s just another Trump attack that he wants people to look at instead of what he’s doing.”

Additional reporting: Sam Stein and Hanna Trudo