Former Vice President Pence is once again at odds with his one-time boss, former President Trump.

Pence on Monday endorsed real estate developer and Arizona Board of Regents member Karrin Taylor Robson in next month’s GOP gubernatorial primary in the race to succeed term-limited GOP Gov. Doug Ducey.

The former vice president called Taylor Robson "the best choice for Arizona’s future" and emphasized in his statement that "as Arizona Democrats pursue the reckless Biden-Harris agenda, Karrin Taylor Robson is the only candidate for governor that will keep Arizona’s border secure and streets safe, empower parents and create great schools, and promote conservative values."

Taylor Robson is one of the two polling front-runners in the Republican primary in a field of four candidates, along with former TV news anchor Kari Lake, who for months has been supported by Trump. The winner of the Republican primary will likely face off in November with Arizona Secretary of State Katie Hobbs, who is the leading contender for the Democratic gubernatorial nomination in the one-time red state that has become a top general election battleground between the two major parties.

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While Taylor Robson and Lake mostly agree on many of the top issues in the Arizona primary battle – such as illegal immigration and border security, the economy and water conservation. While both have issues with Trump’s 2020 election loss to President Biden, Lake heavily supports the former president’s unproven claims that the 2020 presidential contest was "rigged" and "stolen."

Taylor Robson, highlighting the Pence endorsement, said, "He has been a warrior for the sanctity of Life; limited government; law & order; opportunity for all; & the knowledge that our freedoms are granted by God. I’m proud to have him on my team."

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She emphasized that the former vice president "has never wavered in his conservative beliefs & commitment to our Constitution, & left a rock-solid legacy as Gov to which I will aspire."

Trump and Pence

In this Nov. 24, 2020, file photo President Donald Trump speaks in the press briefing room as Vice President Mike Pence listens in Washington.  (AP Photo/Susan Walsh, File)

Both Pence and Trump will be in Arizona on Friday to campaign with the respective candidates they are backing, which will likely lead to split-screen images of the former running mates who may end up facing off against each other in the 2024 GOP presidential nomination race. 

Trump will be headlining a rally in Prescott Valley, Arizona – about 90 miles north of Phoenix – for Lake as well as three other GOP candidates the former president’s endorsed - venture capitalist Blake Masters for Senate, Abe Hamadeh for Arizona attorney general, and state Rep. Mark Finchem for Arizona secretary of state.

Pence will be teaming up with Robson Taylor for two events – one in the Phoenix area and a border security event near Tucson.

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This is Pence’s second high-profile split with Trump in the Republican primaries the past two months. The former vice president endorsed Republican Georgia Gov. Brian Kemp and campaigned with the conservative governor outside of Atlanta on the eve of the state’s May 24 primary. 

Mike Pence and Brian Kemp on the ropeline

Former Vice President Mike Pence and Republican Gov. Brian Kemp of Georgia shake hands with supporters after Pence headlined a primary eve rally for Kemp, on May 23, 2022 in Cobb County, Georgia  (Fox News )

Kemp crushed Trump-backed former Sen. David Perdue in the primary. Trump had repeatedly targeted Kemp ever since the governor certified the 2020 election results in Georgia, where Biden narrowly edged Trump in a key battleground state.

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Trump has also repeatedly slammed Ducey for a year and a half, after the Arizona governor certified Biden’s razor-thin victory in the southwestern battleground state. 

Earlier this month, Ducey made headlines by endorsing Taylor Robson.

"Karrin Taylor Robson is the best conservative in the race for governor," Ducey told Fox News last week. "I've said that I'm going to care very much about who my successor is. And Karrin Taylor Robson is the real deal."

Trump is also at odds with another term-limited GOP governor – Larry Hogan of Maryland.

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Trump last year endorsed state Delegate Dan Cox the Republican primary in the race to succeed Hogan in the blue state of Maryland. Hogan’s backing Kelly Schulz – a former state lawmaker who served as Maryland’s secretary of labor (2015-2019) and secretary of commerce (2019–2022) in the governor’s administration. 

Maryland’s primary is Tuesday.