When the new Monmouth poll hit on Tuesday, the uptick in support for Trump’s impeachment made the headlines.

But further down in the data were a set of numbers that should worry the Joe Biden campaign. A plurality of voters (42 percent) believe President Trump’s tale about Biden pressuring Ukrainian officials to keep them from investigating his son Hunter is probably true. Another 37 percent say probably not, while one in five are undecided.

“Trump may be facing backlash for this [Ukraine phone] call, but the irony is now that its contents are out there, it may actually help with his objective. And that is to sow doubt about Biden among voters,” said Patrick Murray, director of the independent Monmouth University Polling Institute.

Biden defenders dismiss the entire story as “utter bulls***,” and Biden himself told Jimmy Kimmel last week that “I can’t let this distract me in a way that takes me away from the issues that really are the reason why I’m running.” And instead of confronting the allegations, Biden’s campaign sent a letter to cable TV news outlets ordering them to stop putting Trump’s attorney Rudy Giuliani on the air to discuss the Ukraine issue.

But Biden changed his tactics Wednesday night, delivering a blistering attack on President Trump.

“Let me make something clear to Trump and his hatchet men and the special interests funding his attacks against me: I’m not going anywhere,” Biden told a crowd in Reno, Nev. “You’re not going to destroy me. And you’re not going to destroy my family. I don’t care how much money you spend or how dirty the attacks get.”

It sounds like Biden is worried. And the word from pundits and supporters is that he should be.

At Bill Kristol’s NeverTrump, generally Biden-friendly website The Bulwark, veteran political analyst A.B. Stoddard says the Hunter Biden/Ukraine story “could become a fatal blow” to his campaign and that Biden and the Democratic Party should fight back aggressively against what she calls Team Trump’s “lies about Ukraine.”

“The Biden campaign cannot deny the effects of the Trump attacks on his electability argument in the Democratic field,” Stoddard writes, pointing to his sagging poll numbers.

D.C.-based Democratic strategist Joel Payne, who worked on the Clinton ’16 campaign, agrees. “If the question is whether or not Democrats are worried that the president can smear Joe Biden with a steady, daily drumbeat of lies? Yes, absolutely.”

Lies, yes. But what about the truth? Because while many of the attacks from Trump are factually dubious at best, Hunter Biden’s career of collecting unusually large checks from sketchy sources without any apparent reason other than his family connections is beyond dispute. As is Joe Biden’s unwillingness to intervene for the sake of ethical considerations — either as an influential U.S. Senator or the Vice President of the United States.

National Review’s Jim Geraghty recently laid out a detailed timeline recounting Hunter Biden’s history of unsavory connections and problematic behavior while his father held positions of power. It’s not short.

The timeline begins with a questionable hedge fund deal in 2006 (“We’ve got people all over the world who want to invest in Joe Biden,” his uncle reportedly said at the time) and extends across his father’s long and distinguished career.

“Just about any of Hunter Biden’s individual employment or consulting arrangements can be explained as, ‘well, it’s not illegal, but it looks bad, it’s just a lapse in judgment.’ I did the lengthy timeline to demonstrate that this has been Hunter Biden’s whole career  — from MBNA to the lobbying firm to the hedge fund to Chinese private-equity fund Bohai Capital to Burisma Holdings to Chinese energy tycoon Ye Jianming and so on,” Geraghty told InsideSources. “After a while, it stops being an accident and becomes a pattern.”

Or as left-leaning journalist Damon Linker writes at The Week: “Why Biden Won’t Survive the Trump Impeachment.”

Democratic activist Zach Friend, former spokesperson for Obama for America, believes it’s Trump, not Biden, who will suffer the backlash, noting that attacks from fellow Democrats like Sen. Harris have redounded to the vice president’s advantage. “The reality is that the President thought exerting this pressure would shine a negative light on a Democratic frontrunner, but it’s actually boomeranged back to lead him to an impeachment discussion,” he told InsideSources. “Over the course of the campaign, as Biden has been challenged either by Democratic rivals or the President, his support has held pretty steady – as though these attacks have the opposite intended effect and make him a more sympathetic figure.”

Republicans are gloating that, whatever damage the Ukraine story has done to Trump’s standing, they believe it has sent the Democratic front-runner into “Hidin’ Biden” mode, avoiding the press and limiting campaign appearances as difficult questions linger about Hunter Biden’s decades-long career as “a Manafort-level shady dealer,” as one Republican put it.

“This could do real damage to Joe Biden’s 2020 bid because people think of him as that crazy-uncle, goofy, gaffe-prone, but generally likable back-slapping Amtrak enthusiast,” Geraghty said. “People generally did not think of Joe Biden as a D.C. swamp creature, a guy whose family is cashing in on his powerful public office. Biden wasn’t the most articulate, or the smoothest, and he certainly wasn’t young or a fresh face, but people generally thought of him as honest. Well–what if he isn’t? What’s left?”

For Democratic primary voters, what’s left is a large field of 2020 candidates without these difficult questions to deal with–questions the Trump campaign is certain to raise in the general election.