Former Vice President Mike Pence launched his 2024 presidential campaign Wednesday by sharply breaking with former President Donald Trump, laying out clear differences on policy and values and arguing that Trump’s push to overturn the 2020 election should be disqualifying.

Pence, speaking to a crowd of supporters in Ankeny, Iowa, offered his clearest rationale yet for why he is challenging his old running mate for the Republican nomination. Pence accused Trump of wavering on conservative policy priorities such as curtailing abortion access and balancing the budget and bemoaned Trump’s brand of politics as too divisive.

The former vice president also focused extensively on the events of Jan. 6, 2021, when pro-Trump rioters stormed the Capitol trying to stop the certification of the 2020 election, with some chanting, “Hang Mike Pence.”

The day marked a turning point in Pence’s relationship with his old boss, and Wednesday he argued Trump’s attempts to overturn the election — and his request for Pence to violate the Constitution in the process — make him unfit for office.

“The American people deserve to know on that fateful day, President Trump also demanded I choose between him and our Constitution,” Pence said. “Now, voters will be faced with the same choice. I chose the Constitution, and I always will.”

“The American people must know that leaders in the Republican Party will keep our oath to support and defend the Constitution, even when it is not in our political interests,” Pence added. “One last word that in part brings us here today: I believe that anyone who puts themselves over the Constitution should never be president of the United States, and anyone who asks someone else to put them over the Constitution should never be president of the United States again.”

In officially launching his campaign, Pence became the first vice president in modern times to challenge his old running mate for the party’s nomination.

Pence spent four years serving as a loyal cheerleader to Trump, defending him through a steady stream of scandals, vouching for his at-times unorthodox policy decisions and urging Americans in 2020 to give the Trump-Pence ticket four more years in office.

The balancing act Pence will attempt to walk was on display Wednesday, as he said he was “incredibly proud” of the accomplishments of the last administration, even as he sought to argue Trump should not be given another term.

He now faces an uphill battle to overtake Trump at a time when many GOP primary voters view Pence as a traitor for refusing to reject the 2020 election results. Others looking for a Trump alternative appear to be backing Florida Gov. Ron DeSantis (R).

“Given my support for our record, it might be fair to ask why I am challenging my former running mate for the Republican nomination for president,” Pence said. “It begins with a promise I made to the American people and to almighty God, and ends with two different visions for the future of our party and the country.”

A CNN poll released late last month found Pence was the first choice of 6 percent of Republican and Republican-leaning primary voters, trailing Trump, who was the first choice of 53 percent of voters, and DeSantis, who was the first choice of 26 percent.

A Monmouth University poll released last week asked GOP voters who they’d like to see as the Republican nominee for president but did not give a list of names. Pence polled at 3 percent, well behind Trump (43 percent) and DeSantis (19 percent).

Pence and his team intend to lean into the former vice president’s lengthy and consistent conservative track record on foreign policy, trade, entitlement reform and abortion, hoping that message will resonate with GOP voters who want to win general elections, and more specifically with Iowa evangelicals who will participate in the first caucus on the primary calendar next winter.

Pence repeatedly needled Trump on Wednesday as he laid out some of the particulars of his agenda.

The former vice president has vowed to support legislation to restrict abortion access and called on states to do the same. On Wednesday, he said Trump treats the issue of abortion as “an inconvenience,” blaming the issue for Republican election losses.

Pence has called for “common sense” reforms to Social Security and Medicare to address the budget and the solvency of the programs, while Trump has urged Republicans to leave entitlements untouched.

“Addressing a looming debt crisis and long-term survival of Social Security and Medicare are less important than their short-term political fortunes,” Pence said Wednesday.

And Pence, who in his launch video earlier Wednesday said the country needed a leader to appeal to its “better angels,” argued plainly in Des Moines that Trump was not capable of being that leader.

“Most Americans treat each other with kindness and respect — even when we disagree. It’s not too much to ask our leaders to do the same,” Pence said. “It is clear that neither Joe Biden nor Donald Trump share this belief, and neither of them intend to bring this nation together.”

Pence is slated to attend a CNN town hall Wednesday evening in Des Moines, followed by more events Thursday in the Hawkeye State. He will travel to New Hampshire on Friday for a rally in Derry for his first campaign event in the Granite State, which hosts the first Republican primary.