Mike Pence will not endorse the US presidential campaign of Donald Trump, the man for whom he served as vice-president for four years but whose supporters chanted for Pence to be hanged as they attacked Congress on 6 January 2021.

“It should come as no surprise that I will not be endorsing Donald Trump this year,” the former Indiana governor and former candidate for the Republican presidential nomination told Fox News on Friday.

Asked why, given that he previously promised to endorse the eventual nominee, Pence mentioned 6 January 2021, the day when a mob attacked Congress and Trump was reported to have told aides that Pence “deserved” to be hanged for refusing to block certification of Joe Biden’s 2020 election victory.

But Pence placed more emphasis on policies pursued by Trump as he has secured the Republican nomination, a success achieved despite now facing 88 criminal charges under four indictments and suffering multimillion-dollar civil penalties over his business affairs and a rape allegation a judge called “substantially true”.

Pence said he was “incredibly proud of the record of our administration. It was a conservative record that made America more prosperous, more secure, and saw conservatives appointed to our courts in a more peaceful world.”

“But that being said,” Pence continued, “during my presidential campaign” – which he ended in October, months before the first primary vote, in Iowa – “I made it clear that there were profound differences between me and President Trump on a range of issues, and not just our difference on my constitutional duties that I exercised on January 6.

“As I have watched his candidacy unfold, I’ve seen him walking away from our commitment to confronting the national debt. I’ve seen him starting to shy away from a commitment to the sanctity of human life.”

The US national debt ballooned under Trump and Pence.

On abortion rights, the supreme court to which Trump appointed three rightwingers did remove federal rights in 2022, but Republicans have since suffered defeats in a succession of elections in which Democrats have campaigned on the issue.

As Trump claims credit for appointing those justices, Democrats are positioning to make threats to reproductive rights a central issue in this year’s election.

Pence also cited Trump’s “reversal” on “getting tough on China and supporting our administration’s effort to force the sale of … TikTok”.

Pence refused to speculate on why Trump has come out against forcing the sale of TikTok, the social media platform advocates say serves Chinese interests first, by ByteDance, its China-based parent company.

“What I can tell you,” Pence said, “is that in each of these cases, Donald Trump is pursuing and articulating an agenda that is at odds with the conservative agenda that we governed on during our four years.”

“And that’s why I cannot in good conscience endorse Donald Trump in this campaign,” he added.

Most of Trump’s former rivals for the Republican nomination have endorsed him for president. His last such rival, the former South Carolina governor Nikki Haley, has not.