Former U.N. Ambassador Nikki Haley continues to enjoy a post-debate surge, but former President Donald Trump still dominates the GOP presidential field with a thirty-point lead. That was the finding of the latest First-in-the-Nation primary poll, released by Suffolk University Political Research Center Wednesday.

And Republicans hoping anti-Trump Gov. Chris Sununu can stop the former POTUS from winning the nomination may need another plan. Eight out of 10 primary voters said Sununu’s endorsement won’t sway their decision.

Over the summer, a series of polls had Haley at or below five percent in the Granite State. But after two debate appearances widely viewed as successful, she is polling at 19 percent, a solid second place ahead of Gov. Ron DeSantis (R-Fla.) at 10 percent.

“Nikki Haley is kind of on the move in New Hampshire,” David Paleologos, director of the Suffolk University Political Research Center, said on the NHJournal podcast. “What we’re seeing is she’s strong. And what’s unique about her support is that it’s not coming at Donald Trump’s expense. Her growth is coming at the expense of other candidates.”

But she is still far behind Trump, whose share of the vote was 49 percent — and growing.

“Even if you dismiss Haley as the flavor of the month, how many of Trump’s rivals can even boast about that so far?” UNH Political Science Professor Dante Scala asked.

All other candidates polled in the single digits. Notably, former New Jersey Gov. Chris Christie garnered just six percent support in a state he has declared vital to his campaign. Entrepreneur Vivek Ramaswamy and South Carolina Sen. Tim Scott each had just four percent support.

“Christie voters are starting to rotate to [Haley], Scott voters and other voters, Pence voters, so she’s gaining really not at the expense of the front-runner,” Paleologos said. “Trump is still winning by 30.”

The Haley campaign is happy with the new numbers.

“Nikki Haley told New Hampshire she would earn every vote — and that’s what she is doing,” Ken Farnaso, spokesman for Haley’s campaign, told NHJournal. “Nikki has already held more than 50 grassroots events in the Granite State and is coming back next week. Our momentum continues to build, and we’re just getting started.”

Twenty-four percent of Republican primary voters said DeSantis was their second choice, followed by 13 percent for Haley, 11 percent for Ramaswamy, and 10 percent for Scott. Interestingly, only nine percent said Trump would be their second choice for the Republican nomination, while 16 percent didn’t know who their second choice would be.

“I think what you’re seeing in New Hampshire…is that a lot of people like two candidates or three candidates,” Paleologos said, “and for those people, they are rotating to Nikki Haley, and there might be others out there that Haley could win over as well.”

The Suffolk poll is the latest to contradict claims by Trump’s GOP opponents that the former president is struggling in the early states. Trump has a RealClearPolitics polling average of 45 percent in the Granite State, compared to second-place Haley at 14 percent. And Trump’s RCP averages in Iowa (49 percent) and South Carolina (48 percent) are even higher.

And while it is true that Trump is underperforming in early states, that is due to his massive lead in national polling. On Wednesday, a new Morning Consult poll gave Trump 61 percent support, and a new Echelon Insights poll had him at 62 percent.

Not surprisingly, nearly half (48 percent) of Granite State GOP primary voters believe Trump’s nomination is inevitable, while 44 percent believe some other candidate could win the nomination.

“Fifty-nine percent say their mind is made up, mostly Trump voters,” Paleologos told NHJournal. “But another 39 percent say they could change, which opens the door for a potential primary challenger to Trump.”

“The Suffolk poll looks as if it once again confirms Trump has a very solid base of about 35 percent in New Hampshire,” Scala told NHJournal. “A lot of Haley support is not firm, which makes sense given the recent rise. Her support is coming from more moderate Republicans than from conservative Republicans. They’re more significant here than elsewhere, but there are only so many of those voters.”

The most popular politician in New Hampshire, Gov. Chris Sununu, plans to endorse a Republican candidate before the New Hampshire primary. And based on his public statements, it won’t be Donald Trump.

But will it matter? According to the Suffolk poll, 86 percent of Republican primary voters said the governor’s endorsement would not impact their vote. Only 13 percent said they would be influenced when Sununu weighs in.

New Hampshire Republican primary voters picked the border and immigration (37 percent) and the economy and jobs (32 percent) as the most important issues in determining their vote for a particular presidential candidate.

Paleologos said that because New Hampshire allows undeclared and independent voters to vote in its primaries, the Granite State is where a challenger would have the best shot at a Trump upset.

“New Hampshire, when you think about it, includes independents. A lot of states don’t include independents,” he told NHJournal. “Looking at all the states and all the contests, if someone who’s not Trump can’t win in New Hampshire — where else?”

Suffolk University Political Research Center’s survey of 500 likely New Hampshire Republican primary voters was conducted in partnership with The Boston Globe and USA TODAY between September 28 and October 2, 2023. The margin of sampling error for the survey is +/- 4.4 percentage points.