former Vice President Joe Biden enters the stage before the Democratic Presidential Debate at Otterbein University on October 15, 2019 in Westerville, Ohio. Win McNamee | Getty Images

"I think Hunter was more candid than we’ve seen from any Trump child this whole presidency." Rebecca Katz Democratic strategist

Indeed, the debate started with questions about Trump's impeachment. Biden stated forcefully that neither he nor his son did nothing wrong – and that Trump is afraid of facing him. "He's going after me because he knows if i get the nomination I will beat him like a drum," Biden said Tuesday night. Trump, his allies and his personal lawyer Rudy Giuliani — described as a central figure in a whistleblower complaint that helped spur the impeachment efforts — have raised suspicions about Hunter Biden's employment on the board of Ukrainian natural-gas company Burisma Holdings during Obama's presidency. They suggest that the elder Biden improperly pressured Ukraine to fire a prosecutor there out of concern that he would investigate the company. No evidence exists that Biden's actions as vice president were intended to help his son; many Western leaders, in fact, had called on Ukraine to fire that prosecutor over allegations of corruption. Hunter Biden has not been credibly accused of anything illegal related to his work with the company, and unequivocally denied wrongdoing in the ABC News interview that aired in part Tuesday morning. Democratic strategist Rebecca Katz called the interview "a pre-emptive strike" and said Biden will be ready to field questions on the subject at the debate. She also compared the allegations against Hunter Biden to Trump's own children, some of whom have roles in their father's campaign and administration even as they pursue business deals. "I think Hunter was more candid than we've seen from any Trump child this whole presidency," Katz said. "That is the precedent, what's in the White House right now." Feldman predicts that Biden, who has been attacked by Democrats in previous debates, will show more aggression during Tuesday's debate, held at Otterbein University in Westerville, Ohio. But that strategy carries risk. Biden's angry response to an attack by Sen. Kamala Harris, D-Calif., in the first debate, for instance, wasn't well-received among politicos.

Warren rises as Biden slips

Warren is "going to need to have her armor on and be ready," Feldman said. A poor performance could hurt her campaign's upward trajectory, he said, pointing to Harris' campaign, which has lost most of what it gained after her breakout attack on Biden. Sanders, who suffered a heart attack just two weeks ago, may also come out swinging in the debate. At 78, Sanders is the oldest candidate in the race, but he has remained a top candidate throughout the primary, as he was in the 2016 race against Hillary Clinton. Biden is 76, and Warren is 70. Trump, meanwhile, is 73.

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