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Senator Cory Booker has been waiting for this chance for six months.

The New Jersey Democrat, despite having a bigger national profile than many of his rivals in the Democratic primary, has languished in the polls—starved for attention, outshone by competitors both older and younger, and grasping for any kind of traction.

During tonight’s second primary debate, he finally got a clear shot to capture America’s attention, courtesy of former Vice President Joe Biden.

Like others trying to knock Biden out of his top spot in the race, Booker has criticized his competitor’s authorship of the 1994 crime bill, which progressives blame for exacerbating mass incarceration in the United States. He’s also faulted Biden’s more recent proposals for criminal-justice reform as inadequate. Tonight Biden tried to minimize his differences with Booker, saying his plan was “similar” to the senator’s.

Booker wasn’t having it. “This is one of those instances where the house was set on fire and you claimed responsibility for those laws,” he told Biden, who stood next to him onstage in Detroit. “And you can’t just now come out with a plan to put out that fire.”

Biden, in fitting with his feisty style, escalated his critique by calling out Booker’s record as mayor of Newark, New Jersey. He accused Booker of overseeing a police department that engaged in stop-and-frisk, a tactic that’s been widely denounced as racial profiling.

Booker beamed, waiting for his turn to respond. “If you want to compare records—and I’m shocked that you do—I am happy to do that,” he said, drawing laughter from the crowd. “Because all the problems that he is talking about that he created, I actually led the bill that got passed into law that reverses the damages that your bills” created. “You were bragging,” Booker added, “calling it the ‘Biden crime bill’ up until 2015.” Booker was referring to the First Step Act, a bipartisan prison-reform bill that President Donald Trump signed last year.

The duel was a mismatch—a contest between two students who had done the class reading but with only one who was quick on his feet. When Biden tried again to hit Booker for his record in Newark, Booker essentially called him out for reciting a talking point from an opposition-research briefing book and speaking about a subject he didn’t fully know.

“There’s a saying in my community that you’re dipping into the Kool-Aid and you don’t even know the flavor,” Booker snapped, again drawing laughs. “You need to come to the city and see the reforms we put in place.”

Ten-person debates are a poor format for fully litigating policy disputes and historical records, and whether it’s fair or not, visuals and delivery often matter more—at least in the moment. And on that score, Booker clearly prevailed.

He had already cut Biden down once before, accusing the front-runner of having it “both ways” by clinging to Barack Obama’s legacy while disavowing the former president’s heavy-handed use of deportations early in his first term. “You invoke President Obama more than anybody in this campaign,” Booker said. “You can’t do it when it’s convenient and dodge it when it’s not.” (He then shocked the Fox Theatre crowd by invoking Trump’s infamous description of African nations as “shithole countries”—demonstrating in the process that CNN was not broadcasting with a seven-second profanity delay.)

Despite Booker’s well-landed parries and punches, Biden had a stronger performance tonight than he did in June, and whether Booker can translate this debate into a substantial rise in the polls is as yet unknown. But these early debates are far more important for the long shots than the front-runners. Biden has already secured his spot in the next round of debates in the fall, and he’s likely ensured a place onstage until voting starts next year. Booker’s position is considerably more precarious, and for his own immediate prospects, the strength he showed tonight could be that much more valuable.

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