COLUMBIA, S.C. — There's nothing unusual about a politician courting African-American voters at the Alpha Kappa Alpha Pink Ice Gala, an annual fundraiser organized by a chapter of the national black sorority.

But when Sen. Kamala Harris, D-Calif., took the stage, she brought something no presidential contender has before: Membership. She pledged AKA as an undergraduate at Howard University, the historically black college in Washington.

"We stand on the shoulders of women who were leaders, who 111 years ago said to us that we must honor sisterhood and we must honor service," she said in her remarks. "And when we look at where we are this moment, in the history of this country, I think our founders gave us the right charge. They said stand together, take care of each other, and serve your country as leaders."

Harris spoke for less than three minutes before walking off the stage and into a sea of admirers in tuxedos and evening gowns asking for selfies. She stressed afterward that she was in town "as a member of the sorority," not a candidate.

But the setting and Harris' personal connection to the "Divine Nine" of black fraternities and sororities also showcased one reason the senator is seen as a top contender in the Democratic race. She has an opportunity to make a strong pitch to black voters, a group that was decisive in both President Barack Obama's and Hillary Clinton's primary victories and is critical to Democratic hopes of retaking the White House.

In both cases, the eventual nominee won decisively in South Carolina, where 61 percent of the 2016 primary electorate was black, according to exit polls, and then carried their momentum into victories across the south. Black women, who turned out in greater numbers, played an outsized role in the results.

"Across the country we know it's a very powerful bloc," Harris told reporters on Friday when asked about the impact of black women on the race. "We know that, even in the Senate Democratic caucus meetings, there are people who have been elected such as (Alabama senator) Doug Jones who…understand the power of black women to elect candidates and to be a very powerful voice of leadership in the community, equal to everyone else."

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An attendee takes a picture with Senator Kamala Harris during the Alpha Kappa Alpha Sorority Inc. Annual Pink Ice Gala in Columbia, South Carolina, on Jan. 25, 2019. Elijah Nouvelage / Bloomberg via Getty Images

The campaign sees their support as critical to victory. South Carolina is the fourth scheduled primary contest in 2020 and both Obama and Clinton used it to bounce back from losses in New Hampshire, where the electorate is overwhelmingly white. That momentum is especially important for Harris, since her home state of California and eight others vote days later on Super Tuesday.

Her initial campaign rollout has underscored their importance at every turn. She announced her run on Martin Luther King Jr. Day, held her first press event at Howard, and debuted a logo that paid homage to the late Shirley Chisholm's 1972 presidential run, the first major party campaign by an African-American candidate.

"She recognizes black women are the absolute key voters to win over and it's a crowded field," said Aimee Allison, whose organization She The People is hosting a candidate forum in April to address issues facing women of color. The group released a straw poll of activists last month that named Harris the most popular candidate.

The daughter of an Indian mother and Jamaican father, Harris has roots in the African-American community that were a key theme of her recent memoir. In the book, "The Truths We Hold: An American Journey," Harris describes how her mother, who assumed primary parenting duties after a divorce, immersed the family in civil rights activism and took them to a predominantly black church on Sundays.

"My mother used to say, 'You may be the first to do many things, make sure you're not the last,'" Harris said after being asked about being the first AKA member to run for president. "It's about bringing people up."

Senator Kamala Harris speaks to the media after announcing her candidacy for President of the United States at Howard University in Washington, D.C., on Jan. 21,2019. Al Drago / Getty Images

Harris is hardly the only 2020 name putting an emphasis on black voters in the early going. She even had plenty of competition in the same city last week. On the day she announced her run, Sens. Cory Booker, D-N.J., and Bernie Sanders, I-Vt., visited Columbia for an event marking Martin Luther King Jr. Day. Sen. Elizabeth Warren, D-Mass., stopped by later that week.

Doug Thornell, a Democratic strategist, said candidates should be careful not to treat African Americans as a monolith. Black women, senior citizens and millennials have different concerns and candidates will have to tailor their messages carefully.

"(They're) going to have to do the same sort of microtargeting and persuading within the African-American community you would do among white voters," Thornell said. "And if they don't have African Americans in senior decision-making positions and as consultants then they probably should drop out now."

A former state attorney general, Harris has touted her credentials as a "progressive prosecutor" who sought to divert non-violent offenders from jail and combat racial inequality. But she's faced early criticism for siding with prosecutors and police over progressive activists in certain cases.

Booker, who is expected to announce his candidacy soon, and Harris, the only African-American Democrats in the Senate, are considered leading contenders in South Carolina and each has emphasized racial justice in their speeches alongside economic concerns.

But state politicians have also talked up former Vice President Joe Biden as a strong potential candidate, who could position himself as next in line to carry on Obama's legacy. Rep. Jim Clyburn, D-S.C., the state's most prized Democratic endorsement, told The New York Times recently that "everybody else would be running for second place" if Biden gets in the race.

"I really don’t think it's just a Booker/Harris toss-up," said Tameika Isaac Devine, a longtime City Council member in Columbia. "A lot of people still love Joe Biden."

While it helps to have ties to the community, even Obama struggled to win over black voters. Clinton won key endorsements among African-American leaders, including in South Carolina, and Obama only consolidated voter support late in the 2008 primary race after winning the Iowa caucus and allaying concerns about his electability.

Devine, a member of another historic black sorority, Delta Sigma Theta, said Harris' alumni network is a valuable source of early backers, but she plans on grilling candidates on infrastructure, affordable housing and environmental concerns before making her choice.

"It's great someone is part of a fraternity or a sorority, great if someone has some experience on the federal level, but what we really want to know is how they will speak to issues important to us in South Carolina," she said.