Cory Booker
Sen. Cory Booker (D-New Jersey) addresses the crowd during the annual Martin Luther King Jr. Day at the Dome event in Columbia, South Carolina, on Jan. 21, 2019. Getty Images/Sean Rayford

The exchanges between Sen Cory Booker (D-N.J.) and former Vice President Joe Biden, or rather the punches that Booker threw at Biden, were among the most memorable from the second Democratic primary debate Wednesday night.

Biden should have known it coming, with the New Jersey Senator giving a preview last week hitting the former vice president over criminal justice reforms.

On Wednesday, the two again debated on the criminal justice system.

Speaking first, Biden laid out his plans and focused on the changes that he wanted to bring about in the system, including prioritizing rehabilitation over prison and giving prisoners more housing and education opportunities.

In response, Booker wryly pointed out that the current issues in criminal justice exist because of Biden’s work in the Congress. All major and minor crime bills had Biden’s name on it, Booker said. The New Jersey senator argued that it was Biden who pushed for tough laws that led to huge spikes in prison population in the U.S.

Biden deflected the attack and instead insulted Booker’s record as the former mayor of Newark, asserting that nothing happened when Booker was mayor. The former vice president accused Booker of “hiring Giuliani’s guy,” and using stop-and-frisk methods that were seen as illegal.

Booker’s response became became one of the most talked about moments of the night.

“Mr. Vice President, there’s a saying in my community: you’re dipping in the Kool-Aid and you don’t even know the flavor,” he said to laughter and applause from the audience.

The pair then had a go at each other on matters of immigration when Biden suggested that legal immigration should be expanded to automatically include seven-year green cards for PhDs.

“This really irks me, because I heard the Vice President say that if you got a PhD you can come right into this country,” Booker said. “Well, that’s playing into what the Republicans want. To pit some immigrants against other immigrants. Some are from shithole countries, and some are from working countries.”

The comment was not censored in the broadcast, and Booker’s press secretary immediately shared a response on Twitter.

Booker also criticized Biden for trying to play both sides of the Obama card.

"First of all, Mr. Vice President, you can't have it both ways. You invoke President Obama more than anybody in this campaign," Booked said. "You can't do it when it's convenient and then dodge it when it's not."

This came when Biden tried to explain how Obama tried to fundamentally change the healthcare system. Biden played the "I was part of Obama's administration" card when it suited him, but had no reponse to people pointing out that Obama administration deported the most number of illegal immigrants.