Former Utah Governor Jon Huntsman has announced his bid for the Republican presidential nomination.In sight of the Statue of Liberty, Mr Huntsman declared that he respected President Barack Obama but had "a difference of opinion on how to help the country we both love."
Mr Huntsman enters the race at the bottom of the field, and is little-known to the party's electorate.
He most recently served as Mr Obama's ambassador to China from 2009 to 2011.
Mr Huntsman's service as envoy in Beijing until April this year is seen as one of his most significant liabilities, with some staunchly conservative Republicans viewing his work for Mr Obama as a betrayal of the Republican Party.
The son of a wealthy chemical manufacturer, Mr Huntsman rides a motorcycle and plays in a rock band.
He worked as a White House aide under President Ronald Reagan, was ambassador to Singapore under the first President George Bush, and was a trade official under President George W Bush.
Before being elected Utah governor in 2004, Mr Huntsman ran his family's multi-billion dollar chemical manufacturing company.
He is the second Mormon candidate to join the race, along with Mitt Romney, the former Massachusetts governor currently seen as the Republican front-runner.
Debt warning Mr Huntsman said in New York that the US must make "hard decisions that are necessary to avert disaster," a reference to the country's $14.3tr public debt and $1.5tr budget deficit.
"If we don't, in less than a decade, every dollar of federal revenue will go to covering the costs of Medicare, Social Security and interest payments on our debt," he said, referring to healthcare and public pension programmes for older Americans.
"Meanwhile, we'll sink deeper in debt to pay for everything else - from national security to disaster relief."
He is also calling for efforts to reduce US dependence on foreign oil and to create jobs, without laying out specifics policies in either area.
Mr Huntsman opens his campaign with a markedly more moderate tone than those of his rivals, some of whom have questioned Mr Obama's patriotism and loyalty to American ideals.
Low profile "Our political debates today are corrosive and not reflective of the belief that Abe Lincoln espoused, that we are a great country because we are a good country," he said.
"We will conduct this campaign on the high road. I don't think you need to run down someone's reputation in order to run for this office.
"I respect the president," Mr Huntsman continued. "He and I have a difference of opinion on how to help the country we both love.
"But the question each of us wants the voters to answer is who will be the better president, not who is the better American."
Current polls show Mr Huntsman with the support of less than 2% of Republican voters, and some surveys have shown as much as 60% of the primary electorate does not know who he is.
Already in the race are Mr Romney, former House Speaker Newt Gingrich, Minnesota Congresswoman Michele Bachmann, former Minnesota Governor Tim Pawlenty, former Senator Rick Santorum of Pennsylvania, Texas Congressman Ron Paul and Georgia businessman Herman Cain.
Former Alaska Governor Sarah Palin and Texas Governor Rick Perry are thought to be considering running, but have not yet entered the race.