New Hampshire Gov. Chris Sununu to endorse Nikki Haley

New Hampshire Gov. Chris Sununu will endorse GOP presidential candidate Nikki Haley on Tuesday night, three sources close to the Republican governor confirm.

The endorsement in the key early-voting state could further elevate Haley, who has risen in national and state polls in recent weeks in the race for the Republican presidential nomination.

Haley and Sununu are expected to appear together Tuesday night for a town hall, the governor's office said, offering this statement from Sununu: “I look forward to joining Nikki at her town hall this evening — it’s going to be a lot of fun!”

One of the sources said this has been the Sununu team's thinking for some time.

"She’s been here, she’s really pounded the pavement," said one of the people close to the governor. "She’s kind of in the middle, who will bring some peace and calm to the race, at the end of the day."

The endorsement puts an end to the idea that Sununu would get behind Florida Gov. Ron DeSantis, as some Republicans attempt to consolidate support for a candidate besides Donald Trump in the GOP primary.

Haley has held strong in New Hampshire, consistently polling second to Trump.

The Sununu backing is a potential boost to Haley, particularly as she attempts to lay out a compelling argument that she has a path beyond Iowa. Sununu, who is vehemently anti-Trump and flirted with running for president himself, is popular in New Hampshire.

Haley has been polling in second place in the New Hampshire primary for months, but former New Jersey Gov. Chris Christie has also pulled double-digit support in the last two public surveys of the state. Both have been running strong against self-described moderate and independent voters planning to participate in the GOP primary.

Sununu’s endorsement could help Haley consolidate the group and pull closer to Trump ahead of the Jan. 23 primary, though he has long held wide polling leads in the state.

However, it’s also unclear how much of an impact endorsements can make in the early-voting states. A recent NBC News poll found that Iowa Gov. Kim Reynolds’ endorsement of DeSantis barely moved the needle among potential caucusgoers.

The New Hampshire Democratic Party put out a statement calling Sununu and Haley "MAGA extremists who spent years cozying up to Donald Trump."

"Both Sununu and Haley have signed extreme abortion bans with no exceptions for rape or incest, endorsed notorious election deniers like Don Bolduc, railed against crucial programs like the Affordable Care Act, and pushed tax cuts for the ultra rich that left working families behind. Let’s be absolutely clear: there’s nothing moderate, reasonable, or electable about their agenda," the party's statement read.

New Hampshire-based TV station WMUR first reported the news that Sununu planned to endorse Haley.