Jon Huntsman to quit GOP presidential race.

Jon Huntsman will withdraw Monday from the race for the Republican presidential nomination, campaign officials told The Associated Press on Sunday.

The campaign officials spoke on condition of anonymity because Huntsman plans to make the official announcement Monday.Huntsman will endorse Mitt Romney at an event in South Carolina, the officials said. Huntsman believes Romney is the best candidate to beat President Barack Obama in November, they said.

The former Utah governor placed third in last week's New Hampshire primary despite devoting most of his campaign resources to the state. He had already acknowledged that expectations for him in South Carolina's primary this week will be "very low."

Huntsman was routinely at the bottom of national polls, barely registering at 1 or 2 percent.

His resume suggested he could be a major contender for the GOP nomination: businessman, diplomat, governor, veteran of four presidential administrations, an expert on China and on foreign trade. With a personal fortune based on his family's global chemical company, he could be a late entry into the nomination contest without necessarily hobbling his campaign.

Yet Huntsman was almost invisible in a race often dominated by Romney, a fellow Mormon. One reason was timing. For months, Romney and other declared or expected-to-declare candidates drew media attention and wooed voters in early primary states. Huntsman, meanwhile, was half a world away, serving as ambassador to China until he resigned in late April. Nearly two more months would pass before his kickoff speech on June 22 in the shadow of the Statue of Liberty.

To distinguish his candidacy in a crowded field, Huntsman positioned himself as a tax-cutting, budget-balancing chief executive and former business executive who could rise above partisan politics. That would prove to be a hard sell to the conservatives dominating the early voting contests, especially in an election cycle marked by bitter divisions between Republicans and Democrats and a boiling antipathy for President Barack Obama.

Huntsman also tried to offer a different tenor, promising a campaign marked by civility. "I don't think you need to run down somebody's reputation in order to run for the office of president," he said.

While Huntsman was often critical of his former boss -- he joined those saying Obama had failed as a leader -- and occasionally jabbed at Romney, he spent more of his time in debates pushing his own views for improving the economy than thumping the president or his opponents.

In light of his work in the Obama administration, Republicans seemed wary of Huntsman. While he cast his appointment in August 2009 as U.S. ambassador to China as answering the call to serve his country, his critics grumbled that he had in fact been working on behalf of the opposition.