Former US V-P Mike Pence plans to launch presidential campaign on June 7 in Iowa

WASHINGTON - Former vice-president Mike Pence is challenging his one-time boss Donald Trump in a campaign that will put the spotlight on the deep personal rift between the once-close political allies and test whether a party dominated by the former president can accept someone who defied him.

Mr Pence, 63, plans to formally announce his presidential campaign on June 7 in Iowa, according to a person familiar with the plans. 

Mr Pence has been laying the groundwork for a White House bid for more than a year, visiting early-voting states, giving policy speeches and promoting an autobiography.

But he so far has not broken out of the lower tier of 2024 GOP White House aspirants. The RealClearPolitics average of polls has Mr Pence with less than 4 per cent support.

The former vice-president is offering himself as the only traditional conservative in the field who can win the Republican nomination and defeat President Joe Biden – while governing with more civility than Trump.

But Mr Pence has tried to have it both ways, citing popular policies and accomplishments of the “Trump-Pence administration” while breaking from the former president on election denialism and Trump’s praise for Russian President Vladimir Putin.

Mr Pence concedes there are Republican voters who have not forgiven him for defying Trump’s demands to reject Electoral College votes for Mr Biden on Jan 6, 2021. Mr Pence said he did not have the authority, prompting members of the mob that stormed the United States Capitol to chant “Hang Mike Pence.”

Mr Pence has said he is prepared to make the case to voters that he followed the Constitution, and that Trump is wrong to say he had the power to overturn the election and stop the peaceful transfer of power for the first time in US history.

“Look, the people in our party love the Constitution. It’s just we’ve gone through a couple of years where they’ve been told things about what the Constitution says that just aren’t so,” Mr Pence said in an exclusive interview with Bloomberg News on May 16. 

Trump picked the former Indiana governor and congressman – a devout Christian who often introduces himself as “a Christian, a conservative and a Republican, in that order” – to be his 2016 running mate with the aim of shoring up support among evangelical voters. 

Mr Pence has tried to differentiate himself from both Trump and Florida Governor Ron DeSantis, who entered the presidential race last week. He has criticised Mr DeSantis for escalating a fight with the Walt Disney company over its opposition to a law limiting school instruction on gender identity, saying it is not what a conservative, limited-government Republican would do.

But critics question whether Mr Pence has a path to the nomination, given his inability so far to win over hard-core Trump supporters and Republicans looking for an alternative. BLOOMBERG