“I think that that’s part of why Organizing Corps in Milwaukee exists in the first place,” Ms. Cunningham said. “The margins that we can win or lose by in 2020 are field margins, or margins that we, the 30 of us this summer, could potentially make up.”

Though the 2020 election may still feel far off, the goal of the Organizing Corps is to build an early bench of young people of color who are prepared to work in their own communities as organizers and field staff.

Central to the training effort this summer was combating voter suppression in cities. In his stump speech, Mr. Booker frequently references the 2018 governor’s race in Georgia, where Stacey Abrams, the Democratic nominee, was narrowly defeated amid accusations of voter suppression, particularly in black communities.

Though Mr. Booker boasted during the July debate that he was the only candidate talking about the suppression of black voters, the broader Democratic coalition is currently fighting to expand the electorate on both legal and organizing grounds.

The Priorities USA Foundation, a nonprofit group that is separate from the super PAC, is currently involved in voting rights litigation in Iowa, Missouri, New Hampshire and Florida.

The D.N.C. has already created a voter suppression hotline and an online resource guide, and the Organizing Corps has been reaching out in communities that were inundated with misinformation during the last presidential campaign.

Here in Milwaukee, that means focusing heavily on areas like the 53206 ZIP code, in which 95 percent of residents are black and the majority of men have been incarcerated.