ATLANTA — The Rev. Jesse Jackson endorsed Jaime Harrison in his race against Sen. Lindsey Graham in South Carolina, framing his candidacy in an interview with BuzzFeed News as an extension of the civil rights movement’s voting rights agenda and “the emergence of the new South.”

Jackson encouraged Democrats to step up for Harrison at an organizing meeting here in Atlanta sponsored by the Democratic National Committee. Jackson, echoing a sense of optimism heading into 2020 about the party’s ability to motivate black voters across the country, called out Graham by name as he described Harrison’s timing as a threat to Republicans’ stranglehold on statewide elective office across the South. Graham, who has become one of President Donald Trump's highest-profile allies in the Senate, will likely be a popular target for Democrats next year, even in a state that has not elected a Democrat statewide since 2006.

Harrison, who was previously the first black chair of the South Carolina Democratic Party, entered the race in May and so far is running against one Democrat in the primary — Gloria Bromell Tinubu, a former Georgia state legislator who has run for multiple offices in recent years. Rep. Jim Clyburn, a staunch Harrison ally (he worked in Clyburn’s congressional office, and the two are very close), also endorsed Harrison in the race, calling his story “a testament to the enduring vitality of the American dream.”

The news of Jackson’s endorsement of Harrison came both as a significant political development within the state and as a full-circle moment for the legacy of the civil rights movement. Jackson told BuzzFeed News he never thought he’d see a black US Senate candidate in South Carolina because his own parents didn’t have the right to vote. “But we fought for the right to vote,” Jackson said. “And that’s why you never stop fighting.”

Harrison, in turn, told BuzzFeed News that one of his first political memories was Jackson’s speech at the 1988 Democratic National Convention.

“The idea that there was an African American man from South Carolina who ran for president and came close just demonstrated to me that we could do anything,” said Harrison, who wasn’t in the room for Jackson’s endorsement announcement and realized it only when multiple texts popped up on his phone. “So having his faith and his confidence and support means a tremendous amount to me.”

Jackson used his platform Thursday to champion Harrison as a young, dynamic leader with enough promise and name recognition in the state to defeat the incumbent.

“It’s monumental,” said Antjuan Seawright, a Democratic strategist in South Carolina who has ties throughout the state and is supporting Harrison. Seawright said in an interview that in order to be competitive against Graham, it’s critical that Democrats motivate and excite voters in the westernmost part of the state. “An endorsement carries a lot of political weight, and it’s a reminder that Jaime is a representative and beneficiary of the work that icons like him have done over the years,” he said of Jackson’s endorsement.

Harrison is already contrasting himself with Graham, a senator whose closeness to the power of the presidency, Harrison said, has not had much benefit for the everyday people of South Carolina.

“You can be friends with the president, but hell, have it benefit the state in some manner,” Harrison said.

Harrison has been one of the most prominent Democrats pushing the message that the party needs to have a more tangible presence in the lives of local constituencies, helping people with basic services. His national initiative, Democrats Care, will be localized as Harrison Helps, which provides services in each county to help South Carolinians with resources like résumé building, workshops for would-be first-time homebuyers, and volunteer-led health care programs for people in need.

“I have to demonstrate what it means to be a public servant,” Harrison said. “That’s what the job of senator is all about. It’s about being there to help and empower folks so that they can live the American dream.”