COLUMBIA, S.C. — At a funeral service last month, Jannie Jones locked eyes with Democratic Rep. Jim Clyburn across the church sanctuary and crooked a finger, beckoning him to come over to the pew where she sat. She had a question, but she didn’t want to ask it out loud.

The House majority whip bent down so the 76-year-old Jones could whisper in his ear: “I need to know who you’re going to vote for,” she asked.

Clyburn whispered back, “Joe Biden.”

Giving Clyburn a thumbs up, Jones wondered if he’d endorse the former vice president publicly.

“I had no idea he was going to do it,” Jones recalled in a telephone interview with The Associated Press from her home in Hopkins, South Carolina, outside the capital city of Columbia.

Not only did Clyburn go public with his choice among the sprawling Democratic field, just days ahead of his native South Carolina’s pivotal primary, but he also anonymously credited Jones and their whispered conversation with his choice to do so.

“She said, ‘You don’t have to say it out loud, but just whisper into my ear, who are you going to vote for next Saturday? I have been waiting to hear from you. I need to hear from you,'” Clyburn recalled in his passionate endorsement speech, three days before South Carolina’s Feb. 29 vote. “I decided then and there that I would not stay silent.”

The result: Biden handily won South Carolina, bested chief rival Bernie Sanders on Super Tuesday and bumped other hopefuls — Pete Buttigieg, Amy Klobuchar, Mike Bloomberg and Elizabeth Warren — out of the contest in one of the most muscular comebacks in presidential campaign history.

The kingmaker moment was a long time coming for Clyburn, a minister’s son whose congressional career began 27 years ago, after a false start in losing a state legislative race. He rose through the ranks and became the vote-counting House Democratic whip on Nancy Pelosi’s leadership team, the No. 3 Democrat in Congress as well as its highest-ranking black member. And as Republicans rose to prominence in his native South Carolina, Clyburn’s stature in the state increased among its Democratic contingent.

Political endorsements at times aren’t thought of as carrying significant heft, used by candidates and endorsers alike for a momentary media bounce that quickly fades to another name on a list.

But the backing of Clyburn seems to have been the endorsement that brought Biden’s candidacy back from the brink following lackluster performances in other early states. It was an awaited signal for many black voters in South Carolina that Biden would be the candidate to stand up for their interests. He scored a blowout margin of victory of nearly 30 points.

“In our community, as African Americans, we’ve always had a history of hearing from people who have been chosen to lead us,” said Antjuan Seawright. “This example of Jim Clyburn is no different. There’s a reason why I think God preserved him for this moment, to be able to have such an impact.”

Biden has acknowledged the lifeline thrown to him by his friend.

“My buddy, Jim Clyburn, you brought me back,” he said, adding that the congressman had “lifted me in this campaign on his shoulders.”

Biden had long led in surveys heading into South Carolina, where fewer than half of Democratic voters are white. He ultimately won 64% of the ballots cast by African American voters, also performing strongly with older voters, women, regular churchgoers and moderates and conservatives, according to AP VoteCast, a wide-ranging survey of more than 1,400 voters in South Carolina’s Democratic primary.

AP VoteCast results also showed that about a third of South Carolina Democrats said they made a late decision about their vote. Of those voters, roughly half ultimately supported Biden.

As the field constricted and candidates dropped out, Biden’s momentum carried him to victories in 10 of 14 Super Tuesday states. In Alabama, where African American voters made up a majority of the Democratic primary electorate, roughly 7 in 10 supported the former vice president, according to AP VoteCast.

Once Clyburn spoke his mind, said another strategist, Democratic voters of all backgrounds who may have been waffling among the remaining moderate choices saw an imperative to unite behind one of them.

“They got their theoretical permission from Jim Clyburn to do what they needed to do, because they realized the importance of this election, and that the only way that we were going to beat Bernie Sanders, in order to beat Donald Trump, was if we all worked together,” said Amanda Loveday, who has formerly served as Clyburn’s spokeswoman and executive director of the South Carolina Democratic Party. “If your ultimate goal is to beat Donald Trump, it’s time to elect someone who’s going to do that.”

Reflecting recently on that pivotal conversation with Jones, Clyburn said it wasn’t until he had turned to walk away that he realized what she was asking him to do.

“The expression on her face, the look in her eyes when she said it, she just bowled me over with it,” he told The AP. “It was just a combination of stuff. I knew that this lady was asking me to man up.”

Jones, who had never met Clyburn before their exchange, said she was shocked to see him on cable channels crediting her for inspiring him to go public. But, several weeks after the whispers that helped change the political landscape, she said she was elated to have played a role.

“He is a superhero,” Jones said. “I have so much joy in my heart because Congressman Clyburn endorsed Biden.”