U.S. Sen. Johnny Isakson (R-Ga.) addresses current and former staffers at a gathering in Atlanta, Ga. on Tuesday, August 23, 2016. (Karoun Demirjian/The Washington Post)

ATLANTA, Ga.— Here in a state that is both the birthplace of Martin Luther King Jr. and the modern Ku Klux Klan, Democrats and civil rights leaders are worried about the candidacy of Donald Trump.

They argue that the GOP presidential nominee’s disparaging comments about Latinos, Muslims and African-Americans have the potential to reopen old wounds in Georgia, with its racially charged history and where African-Americans make up a third of the population and vote.

Georgia Democrats and civil rights activists want Republicans running below Trump — such as two-term Sen. Johnny Isakson — to loudly denounce their party’s standard-bearer and make it clear that such rhetoric is unacceptable in the modern day South.

“Whether the bigotry targets Mexican Americans or women, black people hear that dog whistle…and that should concern all of us,” said Rev. Raphael Warnock, the senior pastor at Ebenezer Baptist Church, once the parish of King Jr.

Warnock wants Isakson — who has endorsed Trump — to dump the GOP nominee.

“What Trump is doing to our country, to the soul of our nation, is so destructive and so beyond the pale of conventional politics that the normal rules of party loyalty simply do not apply here,” Warnock said in an interview. “[Isakson’s] silence is in fact tacit agreement.”

No one thinks that Isakson condones Trump’s more controversial remarks.

But the senator largely avoids talking about or directly rebuking Trump on the campaign trail, instead arguing that all candidates should respect and reach out to minority voters. And his Democratic opponent —  businessman and first-time candidate Jim Barksdale — isn’t aggressively trying to tie Isakson to Trump.

“I’m not trying to play cheap political games,” Barksdale said in a recent interview. “It’s not my key focus to carry that football down the field at this point.”

But Trump’s rise is helping put Isakson in a surprisingly competitive race against the low-profile Democrat in a state where the presidential polls are unexpectedly tight.

When asked, the GOP senator draws a terse line between his pledge to vote for Trump and the GOP nominee’s frequent epithets, saying he is running his own race and isn’t “going to let somebody else’s race compromise my ability to get reelected.”

“I don’t apologize for anybody else’s comments, I only apologize for my own — they’ve got to apologize for theirs,” Isakson said in an interview last week. “There are lines it doesn’t make any sense for me to cross,” he continued. “It doesn’t mean you’re ratifying or confirming anything, it just means you’ve got a pretty good head on your shoulder

Georgia Republicans, including Isakson, charge Democrats are using Warnock and others to resurrect well-buried racial tensions in an opportunistic bid to up their 2016 chances. (Warnock was approached by Democrats to run against Isakson, he said, but declined.)

And they defend Isakson — and other Republican lawmakers who are at least nominally backing Trump — as not doing long-term damage to the GOP.

“If Donald Trump doesn’t become president, people that didn’t say anything won’t have any apologizing to do because they won’t have anything on record that matches what Trump is saying,” said Robert Highsmith, a Georgia Republican consultant and lobbyist.

The racial politics of 2016, he said, “are not going to have much of an effect in 2018 and 2020.”

But prominent Democrats are counting on the Trump fallout — including support from white nationalists, and the hiring of Breitbart’s Stephen Bannon — dogging the GOP in the future.

“[Isakson] made the choice to embrace Donald Trump, and I don’t envy that decision,” said Jason Carter, grandson of the former president, who lost a 2014 race for governor. “[Republicans] can’t deny the existence of this element in their coalition. It’s opened up schisms that they’re going to have to deal with for a very long time.”

Recent polls show Isakson has only a single-digit lead over Barksdale, though those numbers may belie the difficulty of ousting a well-liked incumbent.

Ask around Atlanta if people have heard of Isakson and most recognize him as their senator; a testament to the incumbent’s reputation for constituent service, even if voters are not as familiar with his record on education, tax policy and veterans’ affairs. Almost no voters interviewed had heard of Barksdale, a political neophyte who wasn’t Democrats’ top recruit.

Democrats say Barksdale’s relative anonymity could be a good thing in their efforts to paint Isakson as part of the problem in Washington.

“Barksdale just has to be an acceptable alternative. I think very few voters are going to go to the polls voting for him,” said Democratic strategist Billy Linville. “He’s not going to win this — it’s Isakson who can lose.”

Republicans’ internal numbers show a less competitive race, but they are still wary that Isakson has not cleared 50 percent. That matters in Georgia, where state candidates must clear that threshold to avoid a nine-week runoff.

At this point, national Democrats have no plans to pour money into the Senate contest, counting anything Republicans are forced to spend protecting Isakson as diverting funds from other competitive contests.  Barksdale, a wealthy investment manager, has already channeled $3.1 million of his own money into the race, and will not say how much more he plans to spend. Isakson had $5.7 million in the bank on June 30 compared to Barksdale’s $1.6 million.

But the tougher-than-expected contest means Isakson needs to placate a variety of constituents. That includes conservative, Trump-loving independents who might vote for Libertarian Allen Buckley if Isakson criticizes the GOP nominee too forcefully. In 2008, Buckley managed to drive the Georgia Senate race into overtime with less than four percent of the vote.

Democrats believe Republican reticence to denounce Trump will accelerate their plans to turn Georgia from red to purple, a strategy that rests on a growing minority population that feels targeted by Trump’s words.

“Every single election is an opportunity to demonstrate who you are and what you will stand for,” said Stacey Abrams, leader for Georgia House Democrats and a rising African-American star in the party. “It’s part of the process: If we win in ’16, we win in ’18, and 2020.”

Republican and Democratic leaders concur that Georgia’s demographic face is changing – and minorities are becoming an increasingly influential part of it. African-American voters already turn out to vote in numbers proportionate to their share of the vote, while smaller but burgeoning Hispanic and Asian-American communities are still trying to increase their electoral participation.

Isakson has long aimed to build ties with minority communities, and in recent years, state GOP officials also started a concerted effort, sponsoring local discussions about juvenile justice reform, policing, and other topics, said Michael McNeely, an African-American and the Georgia GOP’s first vice-chair.

But Democrats have a clear advantage with African-Americans: In a recent Atlanta Journal-Constitution poll, Barksdale pulled 72 percent of black voters, while only seven percent went for Isakson.

Democrats hope anti-Trump sentiment will drive minority groups and women to stage an upset for Clinton and Barksdale. It would be a huge win in Georgia where, with the exception of Bill Clinton’s 1992 election, Democrats have not won a presidential contest since Jimmy Carter in 1980.

But the unexpected opportunity may have come too early for Georgia Democrats, who are still building infrastructure that can carry them to statewide wins. Some minority leaders, particularly in the Latino community, say Democrats are still not ready.

“Both parties were caught off-guard,” said Jerry Gonzalez, executive director of the Georgia Association of Latino Elected Officials.

Democrats’ lack of preparedness is evidenced in Barksdale, who prior to his last-minute decision to run a largely self-funded campaign was a non-entity in Georgia politics. Even now, Barksdale is not sure he will continue to be active in the party if he loses this race.

Barksdale got in the race because “nobody was stepping up,” he said in an interview. He acknowledges his close poll numbers are “a reflection less of me than of how upset people are” with the status quo in Washington.

In fact, Barksdale — who backed Sen. Bernie Sanders (I-Vt.) before endorsing Clinton — hopes he can appeal to Trump voters.

There is a model in Georgia for the rise of a businessman like Barksdale. Two years ago, Georgia elected corporate executive and political newcomer David Perdue to the Senate over Michelle Nunn, despite her family’s legacy in state politics; earlier this year, 155 of Georgia’s 159 counties went for Trump, an outsider, in the GOP primary.

Of course, those winners were Republicans. But Barksdale figures that “economically, people are fed up for the same reasons” with the establishment, of which Isakson is part.

The question is whether or not Barksdale can ride that wave all the way to Capitol Hill.

“Ready or not, here it comes,” he said.