Former Georgia Sen. David Perdue launches primary bid against GOP Gov. Brian Kemp

Perdue's was one of two GOP losses that gave Senate control to Democrats.

Former Georgia Republican Sen. David Purdue on Monday announced a primary challenge against GOP Gov. Brian Kemp, setting off what will be a bitter and competitive primary between former President Donald Trump’s close ally and the sitting incumbent.

With a primary date seemingly far in the distance, Perdue already is running a campaign against 2018 Democratic gubernatorial nominee Stacey Abrams, who announced a second run for the governor’s office last week.

"Look, I like Brian. This isn't personal. It's simple. He has failed all of us and cannot win in November. Instead of protecting our elections, he caved to Abrams. It cost us two Senate seats, the Senate majority and gave Joe Biden free rein," Perdue said.

Perdue and former Republican Sen. Kelly Loeffler lost races for both of Georgia’s Senate seats this year, handing the Senate majority to Democrats, after President Joe Biden bested Trump in November.

The former senator is mounting a challenge from Kemp’s right. Kemp and Republican Secretary of State Brad Raffensperger became frequent targets of Trump’s throughout the year because they did not cave to pressures to overturn the results of the 2020 election.

Perdue and Loeffler called on Raffensperger to resign in the days following the November election, despite no evidence of a reason to do so, aside from the fact that they did not win their races outright and both were forced to runoffs.

"We believe when there are failures, they need to be called out -- even when it's in your own party. ... While blame certainly lies elsewhere as well, the buck ultimately stops with the Secretary of State. The mismanagement and lack of transparency from the Secretary of State is unacceptable," the senators' statement read. "Honest elections are paramount to the foundation of our democracy. The Secretary of State has failed to deliver honest and transparent elections. He has failed the people of Georgia, and he should step down immediately."

ABC News previously reported that in December of last year, while a signature match audit was ongoing in one Georgia county, Trump phoned a chief investigator in Secretary of State Brad Raffensperger's office to discuss the audit, telling the investigator they would be praised for finding errors in the vote count, according to an individual familiar with the call.

In the meantime, Kemp became such an enemy of the former president’s that Trump even endorsed Abrams for her then-unannounced gubernatorial bid in late September.

"And Stacey Abrams, who still has not conceded, and that's OK," Trump said. "Stacey, would you like to take his place? It's OK with me."

" ... Of course having her, I think, might be better than having your existing governor, if you want to know what I think. Might very well be better,” he continued.

Kemp said last week he hoped Perdue would be a "man of his word" when it came to challenging him from the right, referring to Perdue's previous support, but his campaign is ready for a brutal primary if need be.

"Perdue’s only reason for running is to soothe his own bruised ego, because his campaign for U.S Senate failed to inspire voters at the ballot box — twice,” said Kemp spokesman Cody Hall Sunday.

Kemp and Abrams faced off in 2018, and Kemp managed to walk away with a win, although the margin was closer than many Republicans in the state would have liked, at 1.4%. Perdue has privately told allies that he fears Kemp will be unable to beat Abrams in 2022, according to reporting from the Atlanta Journal Constitution.

The terrain is less favorable for Democrats in 2021 as it was in 2022, with Biden’s approval rates plummeting and Republicans able to capitalize on rising inflation rates, among other economic issues.

Democrats are already capitalizing on the GOP infighting.

"While David Perdue and Brian Kemp fight each other, Stacey Abrams will be fighting for the people of Georgia. Both Kemp and Perdue would continue to deprive 500,000 Georgians of health coverage that our taxpayers already paid for," a top Abrams aide tweeted Sunday.

The Georgia Democratic Party is also launching attacks on both Perdue and Kemp.

"Republicans like Brian Kemp and David Perdue have failed Georgians at every level of leadership, and voters can clearly see that the GOP has no real ideas to help working families or move Georgia forward – just conspiracy theories and divisiveness. No matter who emerges from Republicans’ messy, race-to-the-right gubernatorial primary, voters know that Democrats are the only ones who will deliver on the issues Georgians care about, like recovering from COVID-19 and expanding access to health care. Georgia Democrats are more fired up than ever before and looking forward to electing a strong Democratic governor for our state in 2022," Scott Hogan the executive director of the Democratic Party of Georgia said in a statement Monday morning.