CNN  — 

Former Rep. Beto O’Rourke of Texas and South Bend, Indiana, Mayor Pete Buttigieg clashed at Tuesday’s Democratic presidential debate over O’Rourke’s proposed mandatory buyback of assault-style weapons.

The fight over gun policy at the CNN/New York Times debate was sparked when Buttigieg suggested O’Rourke’s proposal was impractical.

“You just made it clear that you don’t know how this is actually going to take weapons off the street,” he said. “If you can develop the plan further, I think we can have a debate about it. But we can’t wait. People are dying in the streets right now.”

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The former congressman responded that mass shootings are a crisis and Democrats should make the case for farther-reaching gun control measures.

“Let’s decide what we are going to believe in, what we are going to achieve, and then let’s bring this country together in order to do that,” O’Rourke said. He called for following the lead of advocacy groups Moms Demand Action and March for Our Lives, the group founded by students after the Parkland, Florida, school shooting last year. He cautioned against being limited “by the polls and the consultants and the focus groups.”

Buttigieg shot back: “The problem isn’t the polls, the problem is the policy. And I don’t need lessons from you on courage – political or personal.”

“Everyone on this stage is determined to get something done,” Buttigieg continued. “Everyone on this stage recognizes, or at least I thought we did, that the problem is not other Democrats who don’t agree with your particular idea of how to handle this. The problem is the National Rifle Association and their enablers in Congress, and we should be united in taking the fight to them.”

O’Rourke said he has never taken on a Democrat who disagrees with him on mandatory buybacks – a dividing issue for the 2020 Democratic field at large – and criticized Buttigieg’s past characterization of the proposal as a “shiny object.”

“I don’t care what that meant to me or my candidacy,” O’Rourke replied. But, he said, to survivors of gun violence, and March For Our Lives, “that was a slap in the face to every single one of those groups, and every single survivor of a mass casualty assault with an AR-15 and an AK-47.”

“We must buy them back,” O’Rourke said.

The two Democratic presidential candidates have traded jabs on this issue before. Their opposing views on gun control highlight their diverging approaches to politics – with Buttigieg seeking to show he is able to stake out a sober middle ground and could function effectively in Washington, and O’Rourke relying on more emotional appeals to those wishing to shake up the political system.

O’Rourke called for a mandatory buyback in the wake of a mass shooting in his hometown of El Paso, Texas. Buttigieg had said before Tuesday’s debate that the proposal played into the hands of Republicans looking for reasons to back away from gun control measures at a time when President Donald Trump and Senate Majority Leader Mitch McConnell were “at least pretending to be open to reforms.”

March For Our Lives tweeted its support of O’Rourke after the debate exchange.

“Thanks for taking a strong stand against gun violence and shouting out the #PeacePlan, @BetoORourke,” the organization tweeted. “AR-15s and AK-47s are not safe for public ownership, and mandatory buybacks will get dangerous weapons of war off the streets.”