MIAMI – New York Mayor Bill de Blasio sought to establish himself an unapologetic progressive during the first Democratic debate here on Wednesday, saying wealthy Americans should pay 70 percent of income in taxes.

“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,” he said.

The NBC debate is the first of two this week. Others who debated Wednesday were: New Jersey Sen. Cory Booker, former HUD Secretary Julian Castro, former Maryland Rep. John Delaney, Hawaii Rep. Tulsi Gabbard, Washington Gov. Jay Inslee, Minnesota Sen. Amy Klobuchar, former Texas Sen. Beto O’Rourke, Ohio Rep. Tim Ryan and Massachusetts Sen. Elizabeth Warren.

The 10 other Democrats are set to debate Thursday.