The multi-pronged effort is a sure sign that Trump's presidential election campaign views Haley as a threat they must neutralize quickly. Trump associates have been reaching out to Haley's top contributors, telling them the race for the Republican nomination is essentially over and suggesting it is time to come into the fold.

"I get calls all the time," said Fred Zeidman, a longtime Haley fundraiser from Texas who said Trump's allies tell him: "'We're going to win. You're going to lose. Don't you want to be on the right team?'"

Zeidman said his response is that Haley can win. "Why would I get out now?" he said. "She's doing everything she needs to do."

The fast winnowing of the Republican field has left New Hampshire as basically a two-candidate race between Trump, the former president, and Haley, who once served as his ambassador to the United Nations.

Polls show the New Hampshire primary on Jan. 23 to be competitive, largely because Haley draws support from establishment Republicans, moderates, suburbanites and independents, who are permitted to vote in the primary. Trump continues to dominate among hard-core conservatives and working-class voters.

Trump's campaign did not respond to inquiries about strategy, but it appears clear the goal is to ensure Haley leaves New Hampshire with little momentum as the fight turns next month to South Carolina, where she served two terms as governor.

Andy Sabin, a metals magnate and Haley backer, said he, too, has been contacted by Trump's allies but isn't ready to jump.

"I don't know in my heart if I can give (Trump) financial support. I just have to be in the mood. And I'm not," Sabin said. "I can't like him as a person. I can't find him likeable. But I do find he was a good president."

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Trump and his forces have stepped up attacks on Haley at campaign events and on television.

At a rally in Atkinson, New Hampshire this week, Trump called Haley a "disaster" and belittled her foreign policy credentials.

"She was not a good negotiator," he said. "She likes to talk about how (she) negotiated with China. I negotiated with China."

Trump's campaign is now deploying former presidential candidate Vivek Ramaswamy, who was sharply critical of Haley in debates, to continue his attacks against her at Trump events.

In a campaign memo earlier this month, Trump's campaign managers Chris LaCivita and Susie Wiles slammed Haley as a phony Republican who would be forced to cobble together a coalition of "non-Republicans and Democrats" to compete.

Between December and January, spending by a top Trump super PAC, MAGA Inc., on negative Haley TV ads jumped from almost $1.6 million to roughly $2.8 million, for a total of almost $4.4 million over the two months, according to data from AdImpact.

One MAGA Inc. ad accuses Haley of being soft on border security, saying she opposed the building of a wall along the U.S. border with Mexico.

The Trump campaign is running TV ads telling voters that Haley seeks to cut Medicare and Social Security benefits, an attack typically used by Democratic candidates against Republicans.

At a rally on Wednesday in Rochester, New Hampshire, Haley made a point of saying such attacks were false. She said she would seek to reform the benefit programs. She defended her immigration record, contending she has always supported the wall.

"Just because you see a commercial...it's not true. I know Trump threw a temper tantrum about me last night, and I have seen the commercials you've seen," she said at the rally. "I will always tell you the truth."

NAME CALLING

Trump has also begun to mock Haley's background in the same way he has done with other women politicians of color such as Vice President Kamala Harris.

In a Truth Social post attacking Haley on Tuesday, Trump referred to her as "Nimrada" - a misspelling of her given first name, Nimarata, saying she had given a "wacked out" speech in Iowa, where she came in a distant third this week behind Trump.

Haley, the daughter of two immigrants from India, was born Nimarata Nikki Randhawa and later took her husband's surname. She has long used her middle name Nikki.

As of Thursday, Trump's post had received more than 17,000 likes and been "re-truthed" over 4,000 times.

A Reuters review of references to "Nimarata" and variations of the name's spelling on social media platforms shows that the name has been appearing in critical Haley posts since November.

Reuters saw an uptick in those references in December, after Haley failed to mention slavery in her response to a New Hampshire town hall question about the reason for the Civil War - comments she subsequently walked back. 

Since Trump's commanding win in the Iowa caucuses, another dynamic has emerged: Donors who want to get in Trump's good graces as he heads toward capturing the nomination to take on Democratic President Joe Biden in the November general election.

Trump fundraiser Ed McMullen, a former ambassador to Switzerland, said DeSantis and Haley donors were now reaching out to him.

He said more than 50 donors had called him in the last week wanting to join Trump, with about 60% of them formerly with DeSantis and 30% with Haley. 

"Iowa is the catalyzing event that awakened people that it's time to get on board," McMullen said. 

Another Republican donor, who asked to remain unidentified, said that after Trump's Iowa victory, he has been asked to come to a face-to-face meeting with Trump at his Florida estate.

"Since Iowa, the calls have ramped up," the donor said. "They say: 'Come down to Mar-a-Lago, let us give you 15 minutes with Trump. Let's put all this behind us and let's focus on beating Biden.'"

The donor said he was turning down the requests for now, but added: "I'll be wearing a MAGA hat by summer."

(Reporting by Alexandra Ulmer in San Francisco and Helen Coster in New York; Additional reporting and writing by James Oliphant in Concord, New Hampshire; Editing by Colleen Jenkins and Alistair Bell)

By Alexandra Ulmer, Helen Coster and James Oliphant