Former vice president Mike Pence won't rule out being Trump prosecution witness

Supporters of Donald Trump send a message to Mike Pence at a campaign event. AFP

The former Republican vice president Mike Pence on Sunday did not rule out being a prosecution witness if his ex-boss Donald Trump goes to trial on charges of orchestrating a criminal conspiracy to try to reverse his defeat in the 2020 presidential election.

Asked on CBS's Face the Nation by Margaret Brennan if he would be a witness against Mr Trump if the case went to trial, Mr Pence said he had “no plans” to testify but did not rule it out.

“But people can be confident we'll obey the law, we'll respond to the call of law, if it comes, and we'll just tell the truth,” said Mr Pence, who is running against Mr Trump in the 2024 Republican presidential nomination contest.

Mr Pence became a central figure in Mr Trump's latest criminal charges on August 1 when a four-count, 45-page Justice Department indictment charged the former president with illegally trying to cling on to power after he had lost the 2020 election to Joe Biden.

Mr Trump pleaded not guilty to all the charges on August 3.

In the run-up to the certification of Mr Biden's win in Congress on January 6, 2021, Mr Pence oversaw the proceedings in his ceremonial role as president of the US Senate.

He came under huge pressure from Mr Trump to overturn the vote and refused. Some of the Mr Trump supporters who rioted at the US Capitol chanted “Hang Mike Pence!”

That incessant pressure and the “contemporaneous notes” Mr Pence took before the riot were frequently cited in last week's indictment.

At one point, the indictment refers to a phone call on January 1, 2021 during which Mr Trump apparently berated Mr Pence for not participating in the scheme to overturn the election result.

“You're too honest,” Mr Trump told him.

Mr Pence's potential testimony and his notes could become key parts of the prosecution case against Mr Trump at trial.

For the first time in the primary campaign, Mr Trump attacked Mr Pence on Saturday. He denied he had called him “too honest”, described him as “delusional” and called him "'Liddle' Mike Pence”.

Mr Pence's presidential campaign has failed to take off so far, meaning he may not even make the first Republican presidential debate this month because of a lack of donors.

He is stuck in low single digits while Mr Trump has become the runaway front-runner, his poll numbers boosted each time he is indicted.

Mr Trump has been indicted three times this year. He has pleaded not guilty in two other criminal cases.

He faces federal charges in Miami for allegedly retaining classified documents after leaving office and obstructing justice, and New York State charges in Manhattan for allegedly falsifying business records to hide hush money payments to a porn star.

Mr Trump could face a fourth indictment this week in Georgia, relating to his alleged efforts to overturn his defeat in the battleground state after the 2020 election.

Mr Pence took on his former boss more forcefully last week, accusing him of surrounding himself with “crackpot” lawyers after his 2020 defeat.

Mr Pence's campaign has sought to profit from Mr Trump's indictment. Last week they began selling hats and T-shirts with a “Too Honest” logo.