Former Vice President Mike Pence filed paperwork Monday to run for president, setting up a clash for the GOP nomination between Pence and his onetime boss, former President Donald Trump .

Pences entry into the 2024 Republican presidential primary sets up an awkward dynamic with his former running mate and ally Trump, who reportedly cheered on calls for Pence to be hanged as hordes of angry Trump supporters stormed the U.S. Capitol on Jan. 6, 2021, to try to stop the certification of the presidential election.

Trump and Pence were aligned throughout nearly all of Trumps presidency but fell out after Trump refused to accept his loss to Joe Biden in the 2020 election. Trump disavowed Pence for carrying out the vice presidents constitutional duty of certifying the Electoral College count, which contradicted Trumps false claims that the results were fraudulent. A former aide told Congress Trump pressured Pence to overturn the election, calling him a wimp. Trump also reportedly didnt dissuade a mob from seeking out Pence in the Capitol to execute him: During the Jan. 6 insurrection, rioters displayed a noose and chanted for Pence to be hanged before the mob broke into the Capitol.

Despite all that, Pence has been measured in his critiques of Trump. His most forceful rebuke of the former president came in March at the Gridiron Clubs annual dinner in Washington.

President Trump was wrong. I had no right to overturn the election, and his reckless words endangered my family and everyone at the Capitol that day, and I know that history will hold Donald Trump accountable, Pence said.

Pence has been signaling for some time that he would run, visiting early voting states and promoting a Christianity-themed memoir, So Help Me God. In May, Pences allies launched a super PAC to support his candidacy, a vessel for big contributions thats independent from a candidates formal campaign.

Scott Reeves, one of the Republican operatives overseeing the PAC, told CNN in May that Pence has the experience, the unparalleled character, communication skills and the conservative credentials to win both the nomination and a general election.

Pence, 63, is framing himself as a traditional conservative in a field of Republicans focused on emulating Trumps combative style and as the candidate most aligned with the religious wing of the party. Pences evangelical beliefs have been a defining feature of his public life the former vice president said in 2017 that he wont eat alone with a woman who isnt his wife, a rule popularized by the late evangelist Billy Graham. He has described himself as a Christian, a conservative, and a Republican in that order.

Unlike many of the Republicans running for president who have treaded carefully around abortion, Pence has embraced stringent restrictions on abortion rights, pledging to support a deeply unpopular national abortion ban if elected. He praised Florida Gov. Ron DeSantis, another 2024 contender, for signing a six-week abortion ban in his state, even though DeSantis himself has shied away from discussing the new law.

Pences refusal to overturn the election in 2020 and the few negative comments hes made against Trump dont seem to have won him any new fans. In April, Pence was booed in his home state of Indiana while speaking at the nations largest gathering of gun rights enthusiasts.

The former congressman and Indiana governor abandoned his gubernatorial reelection campaign in 2016 to become Trumps running mate. Trump, a brash New York City real estate developer and C-list celebrity who paid off a porn star on his way to the White House, had tapped Pence because of his connection to the ultra-religious right.

As vice president, Pence chaired the National Space Council and led Trumps Coronavirus Task Force.

Now Pence and Trump are competing against close to a dozen declared Republican opponents, including DeSantis, Sen. Tim Scott of South Carolina, former United Nations Ambassador Nikki Haley, entrepreneur Vivek Ramaswamy and former Arkansas Gov. Asa Hutchinson, who had all entered the race as of late May.