Julian Castro and Beto O’Rourke’s simmering debate over decriminalizing illegal borders crossings broke out into the open during the first Democratic presidential primary debate.

Castro has centered his presidential campaign around the subject of immigration reform and says illegal immigration should be treated as a civil violation, rather than a crime. During the debate Wednesday night, the former Housing and Urban Development secretary and San Antonio mayor challenged O’Rourke, a fellow Texan and former congressman, on why he didn’t believe the same.

“I just think it’s a mistake, Beto,” Castro said.

O’Rourke defended himself by pointing to legislation he introduced that would “ensure that we don’t criminalize” those seeking asylum. But Castro said he was talking about decriminalizing all border crossings.


“You are looking at one small part of this,” O’Rourke said. “I’m talking about a comprehensive rewrite.”

“That’s not true,” Castro shot back. “I talking about millions of folks — a lot of folks that are coming are not seeking asylum.”

O’Rourke had previously said he didn’t think all border crossings should be decriminalized due to concerns that it would leave law enforcement without legal mechanisms to hold human traffickers and drug smugglers accountable. Castro noted during the debate that his proposal wouldn’t affect the laws against those activities.

The two then proceeded to talk over each other.

According to a Washington Post survey, eight Democratic primary candidates support decriminalizing border crossings — including New Jersey Sen. Cory Booker, Washington Gov. Jay Inslee, and Massachusetts Sen. Elizabeth Warren, who were also on the debate stage Wednesday.

Castro has argued that the idea isn’t unprecedented.

“Between 1929 and the early 2000s, we actually treated it as a civil violation,” he told CNN earlier this week. “So, this is not something radical. This is the way that we used to treat it.”

Earlier in the debate Wednesday night, Castro said he would sign several executive orders to repeal the hardline immigration policies currently in place under President Donald Trump.

WATCH: Castro explains what he would do with immigration on Day 1 as president. #DemDebate pic.twitter.com/q35dZ5mo6U — NBC News (@NBCNews) June 27, 2019