Updated February 17, 2018 18:28:06

Photo: Mitt Romney began his campaigning at a dairy farm in Ogden, Utah. (AP: Rick Bowmer)

Former US presidential candidate Mitt Romney has said he will continue to speak out against President Donald Trump when he feels the need to, despite officially launching his political comeback attempt.

Following months of speculation the 70-year-old has confirmed he will run for a Utah Senate seat, marking the start of his campaign by praising his adopted home state as a model for an acrimonious national government in Washington.

Mr Romney will be the heavy favourite for the Senate seat being opened by the departure of Republican senator Orrin Hatch.

Having been one of the Republican Party's fiercest internal critics of Mr Trump, Mr Romney didn't mention the White House or the President in a campaign announcement posted online.

The closest allusion to Mr Trump was Mr Romney noting that Utah "welcomes legal immigrants from around the world", while "Washington sends immigrants a message of exclusion".

Mr Romney, a former Massachusetts governor, said he would continue to speak out when he takes exception to something the President says or does.

"I call them like I see them. Neither he nor I are likely to change very much," Mr Romney said, adding that they could work together on policy.

"You can expect me to be as forthright as I have traditionally been."

Mr Hatch was among the first Republicans to pitch Mr Romney as his potential successor, and gave Mr Romney a memo last year outlining his case for why he should run, the former presidential candidate said.

Mr Romney said he won't run for president again but wouldn't rule out seeking re-election in six years if he wins Utah's Senate seat this November.

He demurred when asked if he'd seek or accept Mr Trump's endorsement and said he's focusing his campaign on Utah, where he moved with his wife, Ann, after losing the 2012 presidential election to Democrat Barack Obama.

"Utah has a lot to teach the politicians in Washington," Mr Romney said in his announcement video, noting that "on Utah's Capitol Hill, people treat one another with respect".

Endorsement from Paul Ryan, rebuke from Democrats

Photo: Donald Trump greets Mitt Romney in February 2012 after endorsing him as Republican presidential candidate. (AP: Julie Jacobson, file)

After the announcement, House Speaker Paul Ryan — whom Mr Romney chose as his vice-presidential running mate in 2012 — immediately hailed his old partner's "unparalleled experience, conservative leadership and lifetime of service".

Democrats, despite not yet offering any credible threat to the Republican dominance in Utah, answered with a scathing rebuke, dismissing Mr Romney's periodic criticisms of Mr Trump.

"Mitt Romney desperately wants to separate himself from the extremism of the current administration," Democratic National Committee spokesman Vedant Patel said in a statement, adding that "the basis policies of Trump's GOP… were his before they were Donald Trump's."

Mr Romney attracted headlines in 2016 when he took the extraordinary step of delivering a biting speech denouncing Mr Trump, calling him a "phony" who was unfit for office.

Mr Romney muted his criticism for a time when Mr Trump auditioned him as a potential secretary of state.

For his part, Mr Trump has said Mr Romney "choked like a dog" in his failed presidential bids in 2012 and four years earlier, when he lost the GOP nomination to Arizona senator John McCain.

AP

Topics: world-politics, donald-trump, immigration, united-states

First posted February 17, 2018 17:57:30