Iowa. Former Vice President Mike Pence announced his bid for the Republican nomination for president and said Wednesday that Donald Trump should never become president again.

Pence is the first vice president in modern history to challenge the president under whom he served.

He accused Trump of abandoning conservative principles and being guilty of dereliction of duty on Jan. 6, 2021.

On that perilous day, Pence said, as Trump supporters stormed the U.S. Capitol after the president falsely insisted his vice president could overturn the election results, Trump "demanded I choose between him and our Constitution. Now voters will be faced with the same choice.”

“I believe anyone that 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," the former vice president said.

Trump’s statements about mass voting fraud led a mob of his supporters to storm the U.S. Capitol, sending Pence and his family scrambling for safety as some in the crowd chanted, “Hang Mike Pence!”

Pence has spent much of the past two-and-a-half-years grappling with fallout from that day as he has tried to chart a political future in a party that remains deeply loyal to Trump and is filled with many who still believe Trump’s lies that the 2020 election was stolen and that Pence somehow could reject the results.

While Pence has criticized Trump as he has worked to forge an identity of his own outside the former president's shadow, he has generally done so obliquely, reflecting Trump's continued popularity in the party. But in Iowa Wednesday, as Pence made his pitch to voters for the first time as a declared candidate, he did not hold his tongue.

He accused the former president of abandoning the conservative values he ran on, including abortion.

Pence, who supports a national ban on the procedure, said: “After leading the most pro-life administration in American history, Donald Trump and others in this race are retreating from the cause of the unborn. The sanctity of life has been our party’s calling for half a century -- long before Donald Trump was a part of it. Now he treats it as an inconvenience, even blaming our election losses in 2022 on overturning Roe v. Wade."

Trump has declined to say what limits he supports nationally and has blamed some midterm candidates’ strong rhetoric for their losses last November.

Pence also bemoaned the current politics of “grudges and grievances," saying the country needs leaders who know the difference between the “politics of outrage and standing firm."

“We will restore a threshold of civility in public life,” he pledged.

Nonetheless, in an interview with Fox News after his speech, Pence said he will “absolutely support the Republican nominee," even if it's Trump. And during a CNN town hall Wednesday night, Pence said he does not believe Trump should be indicted in the Mar-a-Lago documents case — even if federal prosecutors have evidence he committed a crime.

“I would just hope that there would be a way for them to move forward without the dramatic and drastic and divisive step of indicting (the) former president of the United States," he said. He also refused to say whether, if elected, he would pardon Trump, if Trump were convicted.