But African Americans make up a larger share of the electorate here than they do in any other state, and in recent days, Espy and groups backing him have flooded the state with volunteers, radio ads and social media posts — seeking out potential voters in churches and on historically black college campuses.

“We’re talking to folks who haven’t been talked to in years,” said Ray T. Sykes, a Democratic leader in Coahoma County, where Espy got nearly 70 percent more votes in the Nov. 6 election that preceded Tuesday’s runoff than the Democratic nominee four years ago.

The runoff comes in the aftermath of other elections this year in which black candidates in Florida and Georgia energized minority voters but narrowly lost after enduring racially charged attacks.

GOP anxiety has grown in recent days over the possibility of losing a Senate seat here for the first time in 36 years, prompting President Trump to visit the state Monday night for twin rallies.

Trump’s presence highlighted the divisions of the race, as well as the broader fault lines of American politics that have grown more intense over this year’s midterms. As the president spoke before largely white crowds, Espy headlined a black church event here in the state capital called the “Rise Above Rally and Gospel Explosion,” with passionate prayers, loud music and frequent references to “Senator Espy.”

“Across the chasm of racial acrimony, we are just trying to rise up from all the noise, from all the division, from all the dysfunction,” Espy said in a fiery 30-minute speech in which he recounted racial epithets hurled at him growing up. “And make sure everybody in Mississippi knows: If we gonna rise, we gotta rise together.”

Trump’s first rally was in Tupelo, where Hyde-Smith this month said she would sit with a supporter in the front row of a public hanging.

The comment resurrected memories of the state’s dark racist past and has become one of the most dominant themes of the short runoff election. It also prompted additional scrutiny of Hyde-Smith’s record of defending the state’s Confederate past.

But the president on Monday sought to portray Espy as the one who is out of step with modern-day Mississippi.

“How does he fit in with Mississippi?” Trump asked. “How does he fit in?”

During a Monday morning news conference, Espy refused to link the nooses found outside the state Capitol to Hyde-Smith’s “hanging” comment.

“I can’t connect that to her,” he said. “I wouldn’t do that. That would be unfair.”

Espy and Hyde-Smith, who would be the state’s first elected female senator, are vying for the seat that was long held by Sen. Thad Cochran. He resigned in April because of health issues, and Gov. Phil Bryant (R) appointed Hyde-Smith to fill the seat. Whoever wins the election will fill the last two years of Cochran’s term and then have to run again in 2020.

A runoff is required because no candidate got 50 percent on Nov. 6. Hyde-Smith and another Republican, Chris McDaniel, had won a combined 58 percent, compared with Espy’s 42 percent.

A Hyde-Smith win on Tuesday would hand Republicans a 53-47 Senate majority — representing a net gain in this year’s elections of two seats.

Hyde-Smith has done little to quell the outrage over her public-hanging comments, offering a conditional apology during a debate last week and largely avoiding the issue even as several corporations — including Walmart, Google, Major League Baseball and AT&T — have asked her campaign to return their contributions.

The comments have become a focal point for Espy and his supporters.

Orlando Paden, a state legislator who represents rural parts of Coahoma County, recalled a conversation with his 94-year-old aunt, who said that the comment reminded her, right away, of the scourge of lynching.

“Those types of statements kind of play back in the minds of individuals with a little age, who remember what it was like back then,” Paden said. “Guess what, my great aunt’s absentee ballot is ready, and she’s on the phone calling people.”

Peter Stewart, a 52-year-old volunteer who was traveling on a bus with a national group called Black Votes Matter, said that the comments had been “embarrassing” to all Mississippians but galvanizing for black voters. Awareness of the election had surged since then, he argued.

“Think of a wet firecracker, okay?” he said. “You can’t light a firecracker when it’s wet, but once you get it dry, it lights up even quicker.”

Black Democrats have been reaching voters through a combination of canvassing, social media messaging and direct contact at churches. For weeks, they have had local student leaders record short Facebook and Twitter videos urging their classmates to vote. On Saturday afternoon, local Democrats met and assigned activists to go to 100 churches across the county, each one delivering a letter that reminded voters of the election date, and that Espy was running.

Mississippi Votes, founded to register students on college campuses, expanded quickly as the election approached. Arekia Bennett, the group’s 26-year-old executive director, said nine campuses across the state had Mississippi Votes activists on the ground. At each, when students logged on to campus WiFi, they could see a short Mississippi Votes video about the coming election.

Bennett saw an impact ahead of the Nov. 6 election. In 2014, she said, just 92 students turned out at a polling place near Jackson State University. In November, that number spiked to 351 students. All of that was before the Hyde-Smith gaffe.

“Even if people don’t know about the runoff, they know what she said,” Bennett said.

Groups outside of Mississippi were also sweeping into the state to help in the final days. Woke Vote, founded after the 2016 election by Democratic strategist DeJuana L. Thompson, had raised about $150,000 — some of it from its own leadership — for a three-week get-out-the-vote campaign. Woke Vote’s fliers, which highlighted Hyde-Smith’s “hanging” quote, ended up in the hands of scores of independent canvassers.

“I’ve been telling people about this race all year,” Thompson said at a Sunday night party in Jackson organized by Woke Vote. “What we keep hearing from people is: ‘Oh, no one was in my community before you got here.’ That’s frustrating, but it’s also promising, because we don’t just activate people for one election. We activate them to build black power in their communities.”

Hyde-Smith in recent days has held a handful of public events, but largely avoided answering questions from reporters and has a strategy that is focused on hugging Trump as tightly as possible. She has been traveling on a bus they call the “MAGA Wagon” that has a large photo of her with Trump on the side of it. Radio ads boast about her voting 100 percent of the time with Trump.

And perhaps most indicative of how Republicans perceive the race: The Mississippi Republican Party sent out a mailer urging supporters to get to the polls, but it has Trump’s image and quotes on both sides and never once mentions Hyde-Smith’s name or whom voters are supposed to be supporting.

While there is little evidence that Hyde-Smith has worked to win over black voters — unlike Cochran’s campaign, which courted black voters to help him through a primary four years ago — her GOP allies have taken out radio ads on predominantly black radio stations.

In one spot from Black Americans for the President’s Agenda, a group that drew controversy for an Arkansas ad that warned of Democrats bringing back lynching, two black women discuss how Republican policies have led to “lower welfare dependency and the lowest black unemployment in history.”

Another spot, from Stars and Stripes PAC, attacks Espy for sending a child to private school while opposing school vouchers. “Democrats cry racism, but Republicans are making life better for blacks,” a narrator says.