“If he doesn’t prevail, it’s going to be for lack of resources,” said a close supporter, who would speak about Mr. Huntsman’s financial situation only on the condition of anonymity. “And this is from one of the great wealthy families of America.”

Of course, there are other significant factors at play. Analysts, rivals and even some former aides have wondered aloud in interviews whether he was not his own worst liability, unwilling to run the kind of rock-ribbed conservative campaign that his rivals are using to show their toughness against President Obama — who until 10 months ago was his boss.

And in a climate where the loudest, pithiest voices stand out, he is soft-spoken, given to detailed policy lectures about China, the “trust deficit” in Washington, or his calls to limit the size of banks.

From the start, Mr. Huntsman’s father was prepared to press his network of high-flying associates — and underlings — into the service of raising money for the campaign, two people with knowledge of the early operation said.

The family relationship was already complicated. And while the father is a Mormon church elder who strictly adheres to the religion’s tenets against coffee, tea and alcohol, the junior Mr. Huntsman and his family do not, a choice that especially rankles his mother, family associates say.

Though he lent his campaign some $2 million to help it along, Mr. Huntsman has said publicly that he should be able to raise the necessary money without depending on the family fortune. That stance seemed to signal ambivalence at best about reliance on his father, who had helped start his career by helping him get a low-level job in the Reagan White House.