During Wednesday night’s CNN debate showdown, former Vice President Joe Biden jousted with one of Obama’s Cabinet members over the president’s legacy.

It came when former Housing and Urban Development Secretary Julián Castro called for ending the criminalization of unauthorized border crossings. Then moderator Don Lemon noted that the Obama administration deported almost 800,000 people in the first two years of his presidency. Would deportation numbers go up under Biden?

“Absolutely not,” Biden retorted. “I found that the secretary, we sat together in many meetings, I never heard him talk about any of this when he was the secretary.”

Then protests broke out, and Biden grinned in silence for a few moments until things calmed down.

“We’re in a circumstance where if you say you can just cross the border, what do you say to all of those people around the world who want the same thing, to come to the United States, and make the case that they have to wait in line?” Biden continued. “The fact of the matter is, you should be able to—if you cross the border illegally, you should be able—it’s a crime.”

“People should have to get in line,” Biden added. “That’s the problem.”

Castro didn’t let the topic drop.

“First, Mr. Vice President, it looks like one of us has learned the lessons of the past administration, and one of us hasn’t,” he said.

And to be sure, Castro did criticize the Obama administration’s immigration stance during Obama’s presidency.

Then New York Mayor Bill de Blasio joined the pile-on.

“I didn’t hear whether you tried to stop them or not using your power in the White House,” he said. “Did you think it was a good idea or something that needed to be stopped?”

Biden then pointed to Obama’s move to offer temporary deportation relief—known as Deferred Action for Childhood Arrivals, or DACA—to undocumented people who came to the U.S. as children. And he snapped at de Blasio for comparing President Trump and Obama.

“I think it is absolutely bizarre,” the former vice president said.

The immigration tiff culminated with New Jersey Sen. Cory Booker taking a final shot at the ex-V.P.

“First of all, you can’t have it both ways,” he said. “You invoke President Obama more than anybody in this campaign. You can’t do it when it’s convenient and dodge it when it’s not.”