Four African American mayors from cities in the South are sending a clear warning to the Democratic presidential hopefuls: Don’t forget about us.

The Democratic mayors of New Orleans; Columbia, S.C.; Jackson, Miss.; and Birmingham, Ala.; have signed a letter telling candidates that if they want a chance at their endorsements, they will need to present detailed ideas responding to the challenges facing their constituents.

“The Democratic nomination runs through our communities,” says the letter, which was shared with The Washington Post. “And given the power that we wield in this primary process, we fully intend to use our influence and elevate the interests of our residents to ensure that your campaigns deliver a value proposition consistent with their distinct needs.”

The effort comes amid widespread conversations in the party about how to win white, working-class voters in Upper Midwestern states that tipped the 2016 election to President Trump. It also comes amid a heavy focus on the first two Democratic primary states, Iowa and New Hampshire.

The intent of the letter, the mayors said, is to bring attention to the needs of urban centers in the South that often feel overlooked.

“We’ve got something to say,” said Birmingham Mayor Randall Woodfin. “We weigh in because the national conversation is often removed from what we represent.”

It could also serve to nudge the leading candidates in the polls to try to expand their agendas, as well as the bases of support they are building. Former vice president Joe Biden and Sen. Bernie Sanders (I-Vt.) are in competition for many white, working-class voters, although Biden also has a strong base of African American support, polls show. Sen. Elizabeth Warren’s base tends to be whiter and more affluent.

The letter seeks detailed agendas on affordable housing, infrastructure, criminal justice reform, food policy and other issues. The mayors tell the candidates they represent 345,000 voters, “and importantly, 196 Democratic delegates in 2020 from the states our cities serve.”

It adds: “This letter will serve as a roadmap for your campaigns to engage with us if you wish to seek any of our individual endorsements.”

While some of the candidates have released policy proposals on the topics the letter outlines, the mayors said they would like to see a bigger conversation around them, including in televised debates.

“I do worry that the conversations have not been in depth and substantive enough in the issues articulated in the letter,” said Steve Benjamin, the mayor of Columbia.

After the first two nominating contests in Iowa and New Hampshire, both heavily white, states, the primary battle will shift to more geographically and ethnically diverse terrain, starting with Nevada and South Carolina. On Super Tuesday in early March, Alabama and Arkansas will be among the states casting ballots.

Southern state primaries, in which African American voters play a significant role, hold the potential to tilt the outcome of the race toward or away from candidates. In 2016, Hillary Clinton’s strong showing in the South helped propel her to victory over Sanders.

Beyond the primaries, Democrats have begun thinking about areas in the South as places to expand the map in federal elections. Shifting demographics have made Democrats more optimistic about competing in Georgia, a state the party has talked about turning blue in the near future. Competing for votes in the South now could lay a foundation that could pay dividends down the road, the mayors said.

The mayors, who have spoken to many of the candidates, said that while their endorsement decisions will be shaped by responses to the letter, they intend to decide them individually. And they want their choices to matter.

“We don't want to be an afterthought,” said Jackson Mayor Chokwe Antar Lumumba. “Just like anybody else, we want to be represented.”