ATLANTA (AP) — Former U.S. Sen. David Perdue will challenge Georgia Gov. Brian Kemp for governor, he announced Monday, setting up a bitter 2022 Republican primary fight while Democrat Stacey Abrams is likely to await the winner.

Perdue had been flirting with the bid for months, encouraged publicly by former President Donald Trump. The 71-year-old former senator said he was running to stop Abrams from becoming governor and claimed Kemp would lose to her in November because some hard-core Trump Republicans oppose Kemp.

“To fight back, we simply have to be united,” Perdue said. “Look, I like Brian. This isn’t personal. It’s simple: He has failed all of us and cannot win in November.”

Kemp is promising an all-out brawl as he tries to win a second term, with Kemp spokesperson Cody Hall saying Perdue is running only to “soothe his own bruised ego” over losing his Senate seat.

“The man who lost Republicans the United States Senate and brought the last year of skyrocketing inflation, open borders, runaway government spending and woke cancel culture upon the American people now wants to lose the Georgia governor’s office to the national face of the radical left movement,” Hall said.

Perdue said he would campaign on a platform of entirely eliminating the state income tax, enhancing public safety and empowering parents’ ability to control what is taught in public schools.

But he hit most strongly on hard feelings over Trump’s electoral loss, as well as January Senate losses by Perdue to Democrat Jon Ossoff and by Republican Kelly Loeffler to Democrat Raphael Warnock.

Perdue blamed Kemp for the losses, with a spokesperson pointing to a settlement agreement Secretary of State Brad Raffensperger and the State Election Board made with the state Democratic Party in March 2020 in which the state agreed to set uniform standards for examining signatures on mail-in absentee ballots. Kemp was not a party to the lawsuit.

“Think about how different it would be if Kemp had fought Abrams first before the election instead of fighting Trump,” Perdue said. “Kemp caved before the election and the country is paying the price today.”

Trump-aligned Republicans say the changes led to a smaller share of absentee ballots being rejected statewide, allowing President Joe Biden to win. There is no proof that is true.

Perdue was supporting Kemp as recently as June, introducing him at the state Republican Party convention. Kemp said Thursday that he could not control whether Perdue would be “a man of his word.”

Perdue’s entry could drag Kemp to the right as he vies for primary support. Kemp had hoped to use Abrams’ Wednesday entry to the governor’s race to rally Republicans to his side, but Trump issued a statement after Abrams announced claiming his strongest supporters would never vote for Kemp. Trump has repeatedly targeted Kemp, saying Kemp did not do enough to overturn Biden’s electoral victory in Georgia.

“The MAGA base will just not vote for him after what he did with respect to election integrity and two horribly run elections, for President and then two Senate seats,” Trump said. “But some good Republican will run, and some good Republican will get my endorsement, and some good Republican will WIN!”

Trump’s political action committee commissioned a poll claiming that with Trump’s endorsement, Perdue could beat Kemp in a Republican primary. The former president added fuel to that fire at a Sept. 25 rally in Perry, Georgia, when he pointed out Perdue among a clutch of party leaders.

“Are you running for governor, David?” Trump asked. “Did I hear he’s running?”

Born in Macon, Perdue was a business consultant and then an executive at companies shifting clothing production to Asia. He became CEO of Reebok, textile firm PillowTex and discount retailer Dollar General. The cousin of former governor and U.S. Agriculture Secretary Sonny Perdue, David Perdue was elected to the Senate in 2014, beating Democrat Michelle Nunn.

Perdue joins a slate of Trump-backed candidates in Georgia Republican primaries, including Herschel Walker running against Warnock, state Sen. Burt Jones running for lieutenant governor and Rep. Jody Hice running for secretary of state.

Other Republicans have already been trying to challenge Kemp, including former Democrat Vernon Jones and GOP activist Kandiss Taylor. Jones, who had courted Trump’s endorsement, called Kemp and Perdue “two peas in a pod” on Sunday.

Abrams, whose narrow loss to Kemp in 2018 vaulted her to national fame as a voting rights activist and party leader, has no declared opponents on the Democratic side.

“While David Perdue and Brian Kemp fight each other, Stacey Abrams will be fighting for the people of Georgia,” Abrams top aide Lauren Groh-Wargo wrote on Twitter.

Some Republicans fear a bitter Perdue-Kemp primary will enable Abrams to win. State Sen. Chuck Hufstetler of Rome tweeted Perdue’s entry is “Good news for Stacey Abrams. Bad news for Republicans.”

Emory University political science professor Andra Gillespie said that it’s unclear if a Kemp-Perdue primary would be “demobilizing or demoralizing in a general election” for Republican voters, with some staying home. The national environment in 2022 appears likely to be strong for the GOP, and Gillespie said “Republican voters are going to go vote for a Republican candidate, and they’ll put whatever differences they have aside to support that Republican candidate.”