RENO, Nev. —Former vice president Joe Biden struck a defiant tone during a campaign speech Wednesday night where he ripped President Trump’s efforts to smear him and assured supporters that Trump won’t destroy him or his candidacy.

The top-polling 2020 Democratic presidential candidate has become inextricably intertwined with the impeachment inquiry into Trump’s behavior, which centers on Trump asking a foreign leader for dirt on Biden’s son.

Biden, who spent four decades in the Senate, has in the past sought to separate Trump and his base from the Republican Party that contains his friends and peers, including many he served with as a senator. But in his remarks here, Biden slammed the GOP and “hatchet men” who he said echo Trump’s words.

“He is repeatedly smearing me and my family. His party fans out to carry the smear,” Biden said.

“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,” he said. “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.”

Biden said the attacks by Trump were an attempt to “pick his opponent and go against only the candidates he thinks he can beat. Well, we’re not going to let Donald Trump pick his candidate.”

Democrats have begun to worry that Trump’s relentless attacks on Biden will weigh on the campaign, even if they’re baseless. If Biden is the Democratic nominee there is fear that Trump could succeed in sowing doubt in voters’ minds.

Trump has accused Biden of pressuring Ukraine to fire its top prosecutor in 2016 to benefit his son, Hunter.

Hunter Biden served for nearly five years on the board of Burisma, Ukraine’s largest private gas company, whose owner came under scrutiny by Ukrainian prosecutors over possible abuse of power and unlawful enrichment. Hunter Biden was not accused of any wrongdoing in the investigation. At the time that Joe Biden, then acting in his capacity as vice president, sought to have Viktor Shokin, the Ukrainian prosecutor, ousted, the investigation into Burisma was dormant, according to former Ukrainian and U.S. officials.

Biden and other Western officials have said they were in agreement that Shokin needed to go because he was not sufficiently pursuing corruption cases in Ukraine.

Biden said Trump sought to discredit him and his family because, “like every bully in history, he’s afraid. He’s afraid of just how badly I would beat him next November.”

During a July 25 phone call with the Ukrainian president, Trump asked him to investigate Biden’s son for possible corruption. Republicans have leveled the charge that it was improper for a vice president’s son to sit on the board of a foreign company.

In the roughly 30 minutes that Biden spoke, he didn’t touch on the appearance of a conflict of interest. He said repeatedly that independent news organizations had debunked Trump’s claims.

Earlier Wednesday, during a news conference with the president of Finland, Trump called Biden and his son “stone-cold crooked.”

Biden was asked about Trump and impeachment during a gun-safety forum in Las Vegas and was asked if he had spoken to Hunter Biden about the matter. Biden said they had “communicated a couple of times” but did not offer more detail.

“But look, there is zero, zero, zero, zero evidence of any assertion being made, I’m not going to … look, the issue is this president of the United States engaged in something apparently that is close to, well, engaged in activity that at minimum gives a lot of running room for the Russians and Ukraine and I think we should just focus on the issue,” Biden told the reporters. “Nobody has ever asserted that I did anything wrong except he and what’s that fellow’s name? Rudy Udi? Giuliani?”

cleve.wootson@washpost.com

colby.itkowitz@washpost.com