Nikki Haley set to win New Hampshire governor endorsement

As an early state governor, Mr Sununu’s endorsement holds disproportionate weight, and he has the backing of the majority of Republicans in New Hampshire.

At an event in New Hampshire in November, Ms Haley joked with Mr Sununu: “Are you ready to endorse me yet?”

To the surprise of some observers, he responded: “Getting closer every day.”

The Republican primaries begin on Jan 15 in Iowa, where voters will caucus for their preferred candidate. 

Mr Trump remains ahead there, but Ms Haley and Mr DeSantis will compete for second place in an attempt to become the favoured alternative candidate.

Kim Reynolds, the governor, has endorsed Mr DeSantis for the presidency, prompting Mr Trump to describe her as “the most unpopular governor”.

Responding to reports of Ms Haley’s recent success in the polls, Mr Trump wrote on Sunday night: “Where’s the Nikki Surge? I hear about it from the Fake News Media, but don’t see it in the Polls, or on the Ground.

Using his nickname for Mr DeSantis, he added: “In any event, I hope she and DeSanctimonious are doing well, and continue the same “Surge” as they’ve had for the past eight weeks!”

Mr Sununu has previously said if he chose to endorse a candidate, he would want to “help them put together a campaign, a ground game,” noting that it is “the emphasis, the energy you put behind it, the campaign, the messaging” that “really matters”.