Autumn Johnson, center, joins fellow Hillary Clinton supporters at a Democratic caucus meeting at the Wynn casino in Las Vegas Saturday. (Ronda Churchill/For the Washington Post)

For a few moments, in a conference room deep inside the Wynn casino, the battle for the Democratic presidential nomination came down to a debate between three women of color. Felicia Fletcher, a 44-year-old cashier at the nearby Circus Circus, was one of two undecided voters. Precinct captains for Hillary Clinton and Bernie Sanders descended on her, reducing lifetimes of politics to a few sentences.

“Hillary’s been there for the working people,” said Autumn Johnson, 38, a black woman with a blue Clinton T-shirt and a small American flag pinned in a hair bun. “I know that personally.”

Melanie Malfabon, 26, leaned in a little closer to argue for Sanders. “The banks have lobbyists, and that’s why so many people can’t get ahead,” she said. “His average donation is $37. He’s not owned by big money.”

Finally, politely, Fletcher dropped the poker face. “I trust Bernie more,” she admitted. “But I like Hillary’s views more.”

It was a scene that replayed in hundreds of precincts on Saturday, as Clinton’s loss of altitude in Nevada was halted by a rugged ground game and the resilient affection of black voters.

Why minority voters matter for Democrats in Nevada and beyond

In the same caucus location, hours before the fight for Felicia Fletcher, it wasn’t always easy to see that. The Wynn hosted one of six casino caucuses for employees on the Strip who couldn’t head home to vote. In 2008, 376 people swarmed the caucuses here, a turnout level that had been boosted when the 60,000-member Culinary Workers Union endorsed Barack Obama.

This year, Culinary stayed neutral, and only 60 voters showed up to the Wynn. They came from Circus Circus, from the Westgate and from the arrogantly gleaming Trump hotel across Las Vegas Boulevard. Few of them were white. They walked past a table where Clinton supporters offered blue “I’m with her” T-shirts, then past a throng of volunteers from National Nurses United, the first major union to back Sanders.

In lieu of an endorsement, Sanders volunteers passed out laminated testimonials from casino workers who had come on board — porters, servers, cooks, stage techs. It was a hard sell but a cheerful one. If you had never heard of Sanders, your friends and neighbors had. It echoed the ad campaign that had actually outplayed Clinton in Nevada. And to plenty of voters, it worked.

“He’s an old man with a young spirit, young ideas,” explained Elza Dubrin, 62, a Brazilian immigrant and server at the Wynn who caucused for Sanders. “My son-in-law, he’s a doctor. My daughter, she’s a registered nurse. They both support him 100 percent. So I’ve got to trust them.”

Not far away from Dubrin sat Cedric Wester, 58, a black utility porter who had caucused for Obama in 2008 but could not be convinced that Sanders was presidential timber.

“I love Hillary’s experience,” he said. “She’s more suited for the job than Bernie.”

Hillary Clinton won the Nevada Democratic caucuses on Feb. 20, thanks in part to huge support from black voters and older voters. (Peter Stevenson/The Washington Post)

Suddenly, the chair next to Wester was filled by a smiling Rep. Luis Gutierrez (D-Ill.). “You’re with her?” he said, pointing to female Clinton fans, posing for selfies. “I’m with her, too!”

He was a Clinton endorser, and he was capping off months of attacks on Sanders’s immigration votes by running through the caucus sites to win votes. It was not going so well. Gutierrez, like many Clinton supporters, was out to prove that a quiet majority of hardworking non-white voters was behind her. The caucus process was making that a chore.

“I went down and talked to the workers,” said Gutierrez. “I got kicked out, actually, but before that, I asked, ‘Don’t you want to vote?’ And they said, ‘Yes, but we’d have to take an hour off.’ They’d lose $18 in wages! It’s a poll tax. Nevada’s like the South!”

There was no time to fix that before the vote began. At noon, the doors slammed shut — no one allowed in unless “they say they’ll have a heart attack unless they vote” — and the restless caucus-goers listened to a monotone reading of letters from the candidates. Only after that could they raise their “commitment cards” and declare their votes.

Thirty-four chose Clinton. ­Twenty-four chose Sanders. Two were undecided. Each campaign put its most passionate advocate at a microphone. The Sanders team chose Harold Tavares, a 62-year-old veteran who had come from California to canvass for Bernie and had practiced his speech in the hallway until it got to a crisp one minute.

“We need comprehensive immigration reform that puts families first, and brings people out of the shadows!” Tavares said. “Come with Bernie!”

The lobbying began, and the Sanders team made no converts. Malfabon, who had never been engaged in politics before — who had been an independent, she said, until discovering Sanders — was so adept at explaining the Sanders pitch that her fellow organizers stepped back.

“We all agree on all of these issues,” Malfabon said. “But Bernie Sanders has the power to do it because he’s not owned by big donors.”

Her time ran out, and the room was counted up again. Clinton now had 36 supporters. Sanders had 23, losing a supporter from the first round. Fletcher remained undecided, until the last second, when she raised her card and declared for Clinton.

In this room, Clinton had won. The Sanders volunteers’ cellphones were telling them of bigger wins around the state, so their mood stayed high, even as Clinton was awarded 15 delegates to Sanders’s 9. Fletcher, having helped give Clinton a campaign-rescuing win, had little to say about it.

“I feel like I know her,” she said, “and I know how she’d do in the job.”