Progressives want to extract a concession from former Vice President Joe Biden with his pick for a running mate after they failed to push one of their own to the top of the Democratic 2020 ticket. 

Biden, a centrist who bested more liberal rivals such as Senator Bernie Sanders of Vermont and Senator Elizabeth Warren of Massachusetts on his way to becoming the presumptive nominee, has already vowed to tap a woman as his vice presidential pick. But he will still have to navigate a political minefield to find a Veep who will be the most effective in expanding his appeal and win over skeptical liberals.

“Joe Biden absolutely has to pick a progressive champion as his VP pick. He has to unify the party, and that’s the key,” Charles Chamberlain, head of Democracy for America, told The Hill. “What we saw during the primary is we saw that we have two major factions of this party, the corporate wing, more establishment Democrats, and there is progressive ascendant left. And he absolutely has to choose from that progressive left to unify the party.“

“Running with a vice presidential nominee and the eventual vice president, that person matters in an administration. They bring with them a base, they bring with them followers and supporters, they bring with them a certain set of values and a particular agenda that would have to be taken seriously,” said Maurice Mitchell, the national director of the Working Families Party.

“We’re having conversations with Biden’s team, and trying to figure out what some of these policy conversations will look like. I would love to see the vice president clarify and deepen his policy stances on certain issues,” Representative Alexandria Ocasio-Cortez of New York said. However, she added, “I think it’s incredibly important we support the Democratic nominee in November.”