In the Georgia governor’s race, Geoff Duncan’s candidacy tests American politics as much as it tests his political appeal.

The former Republican lieutenant governor of Georgia is a current Democraticcandidate for governor, with former Biden official and Atlanta ex-mayor Keisha Lance Bottoms currently holding the lead in Tuesday’s Democratic primary. A Republican is still favored to win, with billionaire Rick Jason up against the secretary of state, Brad Raffensperger, and the lieutenant governor, Burt Jones.

Though his candidacy might not prove successful on 19 May, in offering himself to the public, Duncan is asking Democratic voters to consider what the off-ramp for Republican leaders should look like in the waning days of the Trump era. Can it be as simple as switching parties and rearranging one’s political values?

“I think the audience of receptive Republicans is a lot bigger than what most folks would think in the Republican party,” Duncan said. “It’s not fun to have to defend Donald Trump.”

He said that task has become increasingly difficult, even in rural parts of Georgia. “These farmers in these legislative districts have absolutely got a knife in the back from Trump,” he said. “A lot of them voted for Trump in 24, yet now they might lose their farms because of these stupid tariffs that nobody can explain.”

Brushback for opposing Trump is something the former professional baseball player knows acutely.

Both Duncan and Brian Kemp, the Republican governor retiring from public office this year, refused Trump’s extraordinary demands to set aside the results of the 2020 election in Georgia and to call a special session of the legislature to declare Trump the winner. Duncan took to CNN in the weeks following the election to tell Trump to accept the results and to focus on Georgia’s two US Senate contests, rather than continue the contest and “damage the brand”.

Instead, Trump added Duncan to his enemies list.

“Our family received death threats virtually every time Donald Trump went to Twitter and lied about me,” Duncan said in congressional testimony afterward. “We were harassed by Maga disciples almost everywhere we went out in public. Our kids got picked on in school. The list goes on and on and on, all because I was telling the truth.”

Thus began Duncan’s partisan apostasy. He plotted a path for conservatives to emerge in a post-Trump politics, articulated in his book GOP 2.0: How the 2020 Election Can Lead to a Better Way Forward for America’s Conservative Party, which was published in 2021. He testified in the Georgia racketeering case, which brought criminal charges to Trump and his allies, defying Trump’s demand to stay home. He began showing up at Democratic events. He campaigned for Kamala Harris and spoke at the Democratic National Convention.

Georgia has been here before. The southern state had an unbroken line of Democratic governors from Reconstruction all the way to 2002, when Sonny Perdue – who switched from the Democratic to the Republican party as a state senator in 1998 – defeated the Democratic then governor Roy Barnes in a racially polarized campaign after Barnes engineered the end of the Confederate battle flag as part of Georgia’s state standard. The last of the state’s conservative Democrats began switching parties shortly after that, taking the legislature with them.

Today, Duncan says today he has abandoned the hope for a renewed Republican party he articulated in his book.

“First and foremost, the Republican party has sailed their ship over the horizon, it’s gone. There will be nothing left when Donald Trump’s done with it,” Duncan said. “Some of his minions may try to hold the pieces together. I think that’s a foregone conclusion.”

The feeling is mutual, it seems. Georgia’s GOP establishment has meticulously excommunicated Duncan, so much so that it barred him from attending Republican events or even entering property owned by the party. Party officials expunged its records nominating him to elected offices in the past, symbolically recasting a never-Trumper as a never-Republican.

After two sharp losses to Kemp, some Democrats offer a cynical electoral argument for Duncan that might be crass for him to make it himself: that a straight, white committed Christian family man and reformed Republican has a better chance of drawing Republican cross-party voters than a field of candidates who better resemble Stacey Abrams than the last Democrat in the Georgia governor’s mansion, Roy Barnes.

Critics refute this argument by gesturing toward the Rev Raphael Warnock, Georgia’s first Black US senator. But Duncan isn’t offering his relationship with the party or an appeal to racial politics as a selling point. He’s hoping to offer his profile in political courage, and his experience with lawmakers and policymaking instead.

“I can’t just campaign with a bunch of rhetoric and make a bunch of shallow promises and then show up as damaged goods like so many folks winning elections these days,” Duncan said. “I’ve got to actually show up and be willing to do what I said I’m going to do, and that’s build consensus, solve problems, not pick fights, and stay away from just pandering just to get votes. I think that’s part of the coalition that’s coming together to elect us.”

Duncan said he wants to tap Georgia’s burgeoning rainy-day fund – a reserve of about $17bn – to help address childcare costs and reduce poverty. Georgia is one of 10 states that has not expanded Medicaid access; Duncan supports expansion. He would prioritize diverse hiring practices in state government, rejecting the anti-DEI demands of the Trump administration.

And, he would reverse the “heartbeat law” – which he shepherded into passage in 2019 – that officially outlawed most abortions in Georgia once a fetal heartbeat is detected after roughly six weeks of pregnancy.

“I was wrong to think a room full of legislators knew better than millions of women on the issue,” Duncan said. “They don’t. I’ve certainly come to realize in a very real way that women have complicated medical scenarios and deep personal situations that a legislator would never totally ever be able to understand.”

Duncan’s evolution on abortion may raise more doubts about his politics than any other policy transformation he has made, a point he readily concedes in campaign forums. The crowded Democratic race for governor has been relatively free of direct confrontation, though Duncan has drawn more fire than most. “He helped pass the same laws he now opposes,” the state representative Ruwa Romman, a former candidate for governor, told the Atlanta Journal-Constitution when Duncan announced his party switch in August. “He could have expressed these thoughts for years now.”

Duncan’s former Republican colleagues have not hesitated to call his change of position on abortion and other matters opportunistic, particularly the current lieutenant governor and gubernatorial candidate, Burt Jones.

The two have a history. While Duncan was fighting election challenges, Jones was mounting them. Duncan stripped Jones of a committee chairmanship in 2021; Jones subsequently won the lieutenant governor’s race.

Duncan argues for empathy and a focus on policy. Georgia has to prepare itself for life without the federal government’s partnership. “I think that’s what I hear so often in crowds across the state, day after day after day: ‘Can you just go do what you’re promising everybody you’re going to do?’” he said. “Look, there’s no stability at the federal government, there’s no friends of ours in the federal government. Donald Trump certainly doesn’t care about Georgia, he only cares about a status for himself in the mirror or using a sock puppet called Burt Jones.”