Nikki Haley under pressure from donors to defeat Donald Trump in New Hampshire after Iowa caucus loss

• Nikki Haley is facing pressure from some of her top fundraisers to either seriously compete with, or outright defeat, Donald Trump in New Hampshire.
• "I would still like to see her get somewhere but the mountain she has to climb is enormous," said Andy Sabin, a New York businessman and Haley fundraiser. "I don't even know what Trump could do to stop himself right now."
• If Haley falls short, some donors may try to find other ways to stop Trump, including possibly by financing a third party effort like No Labels, said a Republican fundraising advisor.

Former U.N. ambassador Nikki Haley is facing pressure from some of her top fundraisers to either seriously compete with, or outright defeat, Donald Trump in next week's New Hampshire primary, after finishing third Monday in the Iowa caucus.

"I would still like to see her get somewhere, but the mountain she has to climb is enormous," Andy Sabin, a New York businessman and Haley fundraiser, told CNBC. "As much as I like Haley, I don't even know what Trump could do to stop himself right now."

Sabin plans to help raise money for Trump if Haley doesn't make it through the primary season, despite previously telling CNBC he wouldn't give the former president "a f---ing nickel."

"He may be the only choice I have," said Sabin.

Several Haley fundraisers who spoke to CNBC conceded that, unless she gets a very close second to Trump or manages to pull off an upset win in New Hampshire, the race could effectively be over for her after that.

New Hampshire "is critical. If she wins there, and she can, it will be a long primary season," said Eric Levine, an attorney and bundler for Haley.

Levine is also the co-host of a Haley fundraising event scheduled for after the New Hampshire primary. He