The Biden campaign is apparently still shaken from last month’s confrontation with Kamala Harris during the first Democratic primary debate. Until that point Joe Biden had been running a general election campaign, coasting on Obama-era nostalgia, eschewing the grittier aspects of retail politics, and avoiding dustups with lesser candidates. “Creating a sense of inevitability was the goal,” Politico reports. But after Harris knocked him off his perch on the debate stage, Team Biden is said to be recalibrating. He agreed to a rare interview with CNN, Politico notes, and surrogates have started taking more pointed shots at Harris. “Until the debate, nobody had attempted to land a critical punch,” explains former South Carolina Democratic Party chair Dick Harpootlian, referring to Harris’s tactical strike on Biden’s past opposition to federally mandated busing. “They’re responding to deal with issues that arise from someone attacking the vice president’s record.”

With the second round of debates quickly approaching, the Biden campaign is now preparing to play hardball—especially regarding his complicated, nearly four-decade congressional record on various racial issues. “There are people that are all over Joe to get more aggressive,” a source who spoke to Biden tells Politico. “People are very nervous.”

The new strategy was in evidence last week, when Biden initiated a quasi-apology tour for the way he spoke about his former segregationist Senate colleagues, pivoting from “apologize for what?” to admitting it was “wrong” to “somehow give the impression to people that I was praising those men who I successfully opposed time and again.” Biden has also begun attacking opponents more directly for their support of Medicare for All, which would displace Obamacare, and more frequently namedropping Barack Obama.

Whereas at the beginning of his campaign, it seemed like Biden’s people were trying to keep him out of the public eye and let his record do the talking, the candidate is now trying to get out in front of his past. “I think it is true that what you’re seeing [is] a more assertive time in the campaign,” a senior Biden adviser tells Politico. “He’s not going to sit back and let people distort his record, nor is he going to let people define the terms of engagement.”

There are still seven months to go before Iowa, allowing Biden plenty of time to stanch the bleeding. The deeper concern, however, is just how many similar past episodes might be exhumed and relitigated. Prior to the last debate, the conventional wisdom had been that outrage over Biden’s various P.C. transgressions was limited to Twitter, with little purchase in the real world. The majority of the Democratic voters, after all, are more moderate than the progressive voices that dominate online. But Harris’s hit on Biden left a real bruise. Polling taken after the debate found Biden slipping from anywhere between 8 to 10 points, while rivals Harris and Elizabeth Warren saw their favorability rise. Voters may not have agreed with the substance of the attack—when a poll about busing was conducted by the Pew Research Center in 2007, 59% of Americans did not favor it—but the media responded to the optics. Biden looked rattled, confused, slow to counterpunch. The aura of inevitability was off.

Being a front-runner in 2020, it’s becoming clear, requires more than simply positioning oneself as an antidote to Donald Trump. It requires a definitive message of one’s own, the ability to bat off threats, and a willingness to go on the offensive too. So far political operatives are still waiting. “What’s the case he’s going to make? Is it the third term of the Obama administration? Is it ‘fighting Joe Biden’—and what does that mean?” Mark Longabaugh, a Democratic strategist and former Bernie Sanders adviser, tells Politico. “I just don’t think he has laid out compelling elements of his candidacy yet.”

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