MIAMI -- Several of the Democrats running for president found a common target on the debate stage in Miami on Wednesday: Beto O’Rourke.

First, New York City Bill de Blasio sparred with O’Rourke – the former Texas congressman who entered the race to great fanfare, but has since seen his poll numbers decline – over his support for private health insurance plans.

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The spat began when NBC moderator Lester Holt asked O’Rourke if he is for replacing private insurance. After O’Rourke replied “no,” de Blasio interrupted to say, “private insurance is not working for tens of millions of Americans.”

Another candidate, former Maryland Rep. John Delaney, then interrupted to say, “I think we should be the party that keeps what’s working and fixes what’s broken.”

At another point, O’Rourke’s fellow Texan, former HUD Secretary Julian Castro – who has struggled to get attention in the race so far – hit the former congressman for not supporting decriminalizing illegal border crossings.

As the split screen showed O’Rourke and Castro going back and forth, Castro said, “I think you should do your homework on this issue. If you did your homework on this issue you would know that we should repeal this section.”

O'Rourke, for his part, sought to distinguish himself from his rivals by answering several questions in Spanish.

In the spin room after the debate, O’Rourke’s campaign argued he was targeted by de Blasio and Castro because they see him as threat – or as surrogate Gina Hinojosa said, “he’s the frontrunner.”

“I think Beto also set himself apart by engaging with the American public, as opposed to mixing it up with the other people on the stage,” Hinojosa told Fox News.

The attacks on O’Rouke came as some candidates, like de Blasio, unapologetically called for embracing left-wing positions.

“I want to make it clear: this is supposed to be the party of working people,” de Blasio said during the debate. “Yes, we are supposed to be for a 70 percent tax rate on the wealthy.”

The New York mayor, who has struggled to gain traction in the polls, called for the party to embrace other left-wing proposals. It comes amid the rising popularity in the party for socialist proposals, like “Medicare-for-all” and the “Green New Deal.”

“Yes, we are supposed to be for free college, free public college, for our young people. We are supposed to break up big corporations when they are not serving our democracy. This Democratic Party has to be strong and bold and progressive.”