Pence joins current Arizona Republican Gov. Doug Ducey in bucking former President Donald Trump, who endorsed Lake in September 2021, citing her commitment to "election integrity."

Lake has made lies about the 2020 election the central focus of her campaign.

"Donald Trump is endorsing us because he knows we refuse to turn a blind eye to this election of 2020. We are not going to sweep this one under the rug," Lake said in November 2021 after Trump endorsed her. "I would love to see people in handcuffs. And I want a long perp walk that we can watch them all walk. We need to lock these people up."

Lake falsely claims Trump won Arizona's Electoral College votes, even though President Joe Biden carried the state. And she says that she not only would have refused to certify Biden's victory, despite the fact that he won by roughly 11,000 votes in the state, but she would also decertify Biden's victory after the fact.

During a primary debate on June 19, Lake asked her fellow candidates to raise their hands if they agreed with her that "we had a corrupt stolen election." Scott Neely and Paola Tulliani Zen immediately did so; Taylor Robson did not. Robson responded to Lake by saying, "I believe our election was absolutely not fair." She blamed "liberal judges," "liberal media, "Big Tech," and Mark Zuckerberg for creating the conditions for "78 percent of Arizona Republicans thinking something was wrong with the election. But I am focused on 2022 because the left is 10 steps ahead of us and I don't have the time to explain what they're doing."

After the debate, Lake tweeted, "'Would you agree that we had a corrupt, stolen election? Raise your hand' Only one #AZGOV Candidate REFUSED to raise her hand: Karrin Taylor Robson. Disqualifying."

Ducey, who certified Biden's win over the objections of the Trump campaign, said Lake's election lies are a liability.

"Kari Lake is misleading voters with no evidence. She's been tagged by her opponents with a nickname, Fake Lake, which seems to be sticking and actually doing some damage," Ducey said Sunday on CNN's "State of the Union."

"It really is so sad to see @GOP Governor @DougDucey join the Propagandists at @CNN to blast Trump AND the Trump-Endorsed Republican candidate," Lake tweeted after Ducey's appearance on CNN. "I just can't figure out why he doesn't support our America First Movement."

A poll of likely Republican voters in Arizona conducted by OH Predictive Insights between June 30 and July 2, 2022 found Lake leading Robson 40%-35%, with 21% remaining undecided ahead of the Aug. 2 primary.

Early voting began in Arizona on July 6.

That day, Trump reiterated his support for Lake, saying in a statement, "With Kari, you'll have Election Integrity, Strong Borders, Safe Streets, and all of the other things you've wanted for so long. Vote for Kari Lake. She has my Complete and Total Endorsement!"

On Friday, Trump and Pence will hold competing rallies for their respective picks for governor.

While it's so far unclear how much the endorsement battle will impact the primary vote, Pence's stock among Republicans has fallen considerably, with just 6% of GOP voters responding to a New York Times/Siena College poll conducted July 5-7 that they would vote for Pence if he ran for president in 2024.

Trump meanwhile remains widely popular among Arizona Republicans, with 81% having a favorable opinion of the former president, according to the OH Predictive Insights poll.

Inside Elections, the nonpartisan political handicapping outlet, rates the Arizona gubernatorial general election a toss-up.

FiveThirtyEight's aggregate of polls currently shows Hobbs with a lead against both Robson and Lake. The lead is larger over Lake.