Nikki Haley clinches the endorsement of New Hampshire’s popular Gov. Chris Sununu as she tries to position herself as the best Trump-alternative in the GOP field over Florida Gov. Ron DeSantis

Republican presidential candidate Nikki Haley will be endorsed by popular New Hampshire GOP Gov. Chris Sununu at an event in Manchester on Tuesday night.

Sununu’s endorsement comes as the former U.N. ambassador and South Carolina governor tries to position himself as a leading alternative to Trump in a shrinking 2024 GOP field.

Standing in her way is Florida Gov. Ron DeSantis, whom she beat in New Hampshire but still leads Haley in the Iowa polls.

National polls show DeSantis still slightly ahead of Haley, but the gap is narrowing.

DeSantis was previously endorsed by popular Iowa Gov. Kim Reynolds, and Haley tried to replicate that with Sununu in New Hampshire.

Republican presidential candidate Nikki Haley (left) will be endorsed by New Hampshire Gov. Chris Sununu (right) in Manchester on Tuesday night as she seeks to become the top GOP alternative to Trump in the 2024 primary.

Nikki Haley wrote on X Tuesday that it would be a “great day in New Hampshire with Gov. Chris Sununu” after news broke that she was receiving his endorsement.

Sununu announced in June that he would not run for the White House and in July that he would not seek re-election after serving four terms as governor of the Granite State.

The moves allowed him to devote his time to finding Trump’s replacement as he argued the former president must go.

“Republicans will lose again,” he predicted in the June issue article for The Washington Post.

“We must not be complacent, and candidates must not enter this race to further a vanity campaign, to sell books, or to audition to be Donald Trump’s vice president,” he wrote.

“Since 2017, the national Republican Party has suffered losses on the ballot, in red and blue states, and in elections spanning the House, Senate and presidency,” he continued. “It will happen again unless we Republicans correct course.”

Sununu also memorably called Trump “fucking crazy” during the annual Gridiron Dinner in Washington in 2022.

Message first reported about Sununu Haley’s upcoming endorsement.

New Hampshire Gov. Chris Sununu (left) stands next to Nikki Haley (right) at a campaign stop in Hooksett late last month. Sununu seeks Republican nominee to take on Trump in two-way primary

Sununu argues that the GOP field simply needs to be narrowed for Trump to lose.

It’s unclear whether he will call on the remaining viable candidates – DeSantis, New Jersey Gov. Chris Christie and entrepreneur Vivek Ramaswamy – to drop out when he appears with Haley on Tuesday night.

But during a September appearance at the Texas Tribune Festival in Austin, the governor said candidates should drop out of the race, “hopefully before Super Tuesday.”

The Iowa caucuses will be held on January 15, and the New Hampshire primaries will be held on January 23. Super Tuesday will be on March 5th next year.

“Candidates need discipline and accountability to get out,” Sununu said. “Since he loses in a one-on-one match, there is no doubt about it. He’s not going to retain 50 percent of the vote if it’s head-to-head… if seven or eight candidates show the discipline to come out, he’s toast.”

Sununu’s appearance with Haley in Manchester on Tuesday night will come around the same time DeSantis headlines a CNN town hall with Iowa voters.

In a statement to DailyMail.com, a spokesperson for Christie, who is largely focused on winning New Hampshire, shrugged her support for Sununu Haley.

“We’ve seen reports of Governor Sununu’s decision to support Nikki Haley. This leaves us one vote short in New Hampshire, and when Gov. Christie returns to Londonderry tomorrow, he will continue to tell the unvarnished truth about Donald Trump and earn that one missing vote and thousands more,” said Christie spokesman Carl Rickett.