ATLANTA (AP) — Former Vice President Mike Pence is making an in-person push for Gov. Brian Kemp’s reelection a day before the Republican incumbent faces his biggest challenge from a candidate backed by Pence’s old boss.

Pence was scheduled to rally with Kemp in suburban Atlanta on Monday evening. Ex-President Donald Trump, meanwhile, planned to hold a telephone rally in the evening to champion the candidacy of former U.S. Sen. David Perdue. Trump urged Perdue to enter the race as retribution for Kemp not going along with Trump’s effort to overturn his loss to President Joe Biden in Georgia in 2020.

More than 850,000 people already voted early, including more than 483,000 who chose a Republican ballot and almost 369,000 who chose a Democratic ballot. Georgia has no party registration, so voters can choose which primary to vote in when they go to the polls.

Turnout could exceed the 2018 primary, when 620,000 Republicans and 563,000 Democrats voted.

Pence’s latest political break with Trump is capturing much of the attention on the final day of the campaign. Pence became the most recent Republican figure to rally to Kemp’s side. The Republican Governors Association also ran an expensive effort to defend Kemp.

“I think it just shows that Republicans not only in the state, but around the country are rallying to the person that can beat Stacey Abrams,” Kemp told reporters Monday morning as he continued to focus on the Democrats’ standard-bearer, who is unopposed in her party’s primary.

Kemp downplayed the split in the GOP, saying party leaders often have different choices in the primaries.

“I wouldn’t tell people to read too much into that,” he said.

Rainy weather in the state was hampering some plans. Kemp and Republican candidate for lieutenant governor Butch Miller both canceled plans to make a flying tour of Georgia cities. Other candidates continued to look for a boost from Trump. The former president is also scheduled to conduct a telephone rally Monday night for John Gordon, the neophyte candidate whom Trump endorsed in a Republican primary challenge to incumbent Georgia Attorney General Chris Carr.

In Georgia’s U.S. Senate primaries, Democratic incumbent Raphael Warnock has only token opposition, while on the Republican side Trump-backed candidate and former football great Herschel Walker was running against five GOP challengers, including Georgia Agriculture Commissioner Gary Black and former Trump administration official and Navy veteran Latham Saddler. A general election matchup between Warnock and Walker in November would mark the first time that two major party candidates for U.S. Senate in Georgia were Black.

For Kemp, an outright win in the primary would be vindication after months of attacks from Trump.

Perdue embraced Trump’s election lies, opening two debates between the candidates with the claim that the 2020 balloting was “rigged and stolen.” He also joined a lawsuit meant to force a physical examination of ballots in Atlanta’s Fulton County. State and federal officials, including Trump’s own attorney general, have said there was no evidence of widespread fraud. The votes in Georgia’s presidential election were counted three times, and each tally confirmed President Joe Biden’s victory.

Trump conducted a rally in Georgia in March for Perdue and other candidates and kicked in more than $3 million for ads attacking Kemp. But Perdue has had trouble raising money and gaining traction against Kemp, and the Republican Governors Association has outspent Trump with its own ads aiding Kemp.

Kemp, meanwhile, benefited from being able to hand out pay raises and tax cuts using overflowing state revenues. He announced two electric vehicle plants and was able to sign conservative-pleasing laws that put an end to permit requirements to carry a concealed handgun and that paved the way for transgender girls to be banned from playing high school sports.