WASHINGTON – A presidential forum focusing on issues important to women of color has drawn four more Democratic hopefuls, signaling the key role these women are likely to play in the 2020 battle for the party’s nomination.

In a nod to the political power of women of color, seven Democratic presidential candidates will lay out their agendas at a forum April 24 at Texas Southern University, a historically black institution in Houston.

Sens. Bernie Sanders, an independent who caucuses with Democrats, Amy Klobuchar of Minnesota and Elizabeth Warren of Massachusetts, as well as Rep. Tulsi Gabbard of Hawaii, will attend the forum hosted by She the People, organizers confirmed in an exclusive to USA TODAY.

“We’ve set the table, and we’ve invited everybody to dinner,” said Aimee Allison, president and founder of She the People. “We want to have this conversation. … Women of color are voting like our lives depend on it. It does."

Candidates who previously confirmed their attendance include Sen. Cory Booker of New Jersey, former Rep. Beto O’Rourke of Texas and former Housing and Urban Development Secretary Julian Castro. Organizers of what is billed as the first presidential forum hosted by women of colorinvited all declared Democratic presidential candidates. Seven of the eight spots reserved for candidates at the forum were filled by Friday.

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“If you’re serious … you recognize that you will not win the primary without a very significant enthusiastic support of women of color," Allison said. “And not a single candidate has a lock on women of color voters in the early states, so our forum is a big moment. We want these campaigns to make their case."

Marc Morial, president of the National Urban League, said presidential candidates should jump at the chance to participate. Last year, the organization launched "Enough is Enough," a national get-out-the-vote campaign to get more blacks politically engaged.

“African American voters, particularly African American women voters, are crucial to the road to the White House," Morial said. “I just believe that anyone running for president today is a fool to ignore black voters, particularly black women voters.”

Black women's groups led get-out-the-vote efforts across the country last year, including in high-profile races that helped Stacey Abrams in Georgia and Andrew Gillum of Florida win their Democratic gubernatorial primaries and come close to victory.

Black women also helped Democrat Doug Jones pull off an upset in the 2017 Senate race in Alabama, a ruby-red state.

The groups backed women candidates of color who made this Congress the most diverse in history.

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Leaders of national groups led by women of color have long complained that some Democratic candidates take their support for granted. Women of color, particularly black women, historically tend to support Democrats.

‘‘We’re now collectively flexing our power … to ensure these candidates don’t take us for granted,” said Glynda Carr, co-founder of Higher Heights, a group that supports black female candidates and more black political involvement and is a national partner of the forum. “It can’t be business as usual.”

Forum organizers, which include several Texas-based groups, expect as many as 1,000 participants from 28 states. Many are coming from Southern states, including Louisiana, Georgia and Florida, a swing state.

At the forum, candidates will appear by themselves on stage where they will have 20 minutes to speak and answer questions, including some from the audience. Organizers said the candidates will be pressed on such issues as criminal justice, immigration, voting rights and climate change.

Candidates will have to go beyond "we’re opposed to Trump,” Allison said.

“We are not interested in platitudes," she said. “We want people to present plans. We hope to cover new ground.”