President Biden’s decisive victory within the New Hampshire Democratic presidential major supplied him with a dose of excellent political information amid a season of Democratic anxiousness about his marketing campaign.

The symbolic, if largely anticipated, win on the energy of a write-in marketing campaign comes as Mr. Biden and his celebration now shift extra absolutely into general-election mode after former President Donald J. Trump triumphed within the state’s Republican major on Tuesday. He beat Nikki Haley, the previous governor of South Carolina, although she has vowed to proceed her uphill battle in opposition to him.

“It is now clear that Donald Trump will be the Republican nominee,” Mr. Biden mentioned in an announcement, by which he thanked voters who wrote in his identify. “And my message to the country is the stakes could not be higher.”

Mr. Biden is anticipated to marketing campaign this weekend in South Carolina, which he and the Democratic Nationwide Committee chosen to supplant New Hampshire because the first-in-the-nation major.

He declined to look on the poll in New Hampshire after the Granite State refused to simply accept its demotion. However his allies within the state ultimately stepped in, and the write-in effort, supported by high Democrats there, generated the type of grass-roots vitality for Mr. Biden that has not but materialized in different states — and that he didn’t take pleasure in in New Hampshire’s major in 2020, when he got here in fifth place.

Kathy Sullivan, a former chairwoman of the New Hampshire Democratic Social gathering who led a write-in Biden tremendous PAC, mentioned {that a} robust Biden displaying within the state was essential “to counteract the narrative that’s out there that he’s not popular” and to sign that he had the assist of the Democratic base.

The decisiveness of Mr. Biden’s write-in victory over the long-shot challenger Dean Phillips, a Minnesota congressman who was considered one of 21 Democrats on the poll, made the state’s insistence on voting first much more significant, she added.

“We go into the general election now,” she mentioned.

However earlier than the overall election formally arrives, Mr. Biden will take part within the Democratic major contests subsequent month in South Carolina, Nevada and Michigan. These races will take a look at the Biden marketing campaign’s potential tomobilize its most loyal voters, as polling has proven indicators of weak point with core base constituencies. He’s anticipated to handle a gathering of South Carolina Democrats on Saturday.

In New Hampshire, Mr. Biden’s absence on the poll left him uncovered to a group of opponents who had just about no shot of profitable the nomination however who noticed a possibility to win consideration.

That group was led by Mr. Phillips, who pushed a message of generational change, denounced Mr. Biden, 81, as “unelectable,” and spent heavily on promoting as he highlighted the president’s snub of the state. One among his ads featured Bigfoot searching for Mr. Biden.

Mr. Phillips sought to faucet into Democratic discontent with the president, which was evident on the bottom.

“There should be a benchmark of 65, 68, 70 for being president,” mentioned Richard Valley, 53, who lives in Manchester and voted for Mr. Phillips, who’s 55 years outdated. “You need to be agile. You need to be in tune. You need to be at a higher level. You’re the leader of the free world!”

Mr. Biden’s allies argue that when People focus extra squarely on the election, particularly on the prospect of one other matchup in opposition to Mr. Trump, disillusioned Democrats will rally across the presumptive nominee.

One such Democrat is Tiffani Cardinale from Harmony, N.H. “To be honest with you, Joe Biden is not my favorite president,” she mentioned. “But I’m very scared of what the alternative could be.”

She mentioned that she solid a write-in vote for Mr. Biden within the major, including that she was involved concerning the state of American democracy.

On Tuesday night time, Mr. Phillips congratulated Mr. Biden at his watch celebration in Manchester, saying that the president “absolutely won tonight” — however, he added, “by no means in a way that a strong incumbent president should.”

Amid issues from Democrats concerning the Biden marketing campaign’s construction — and as his group gears up for a bruising basic election swiftly coming into view — the president permitted a management shake-up on Tuesday that may see two high White Home aides take over practical management of the re-election effort.

The drama over this yr’s nominating calendar started in late 2022, when Mr. Biden and the D.N.C. determined to reorder it, saying that Democrats ought to give states with extra racial variety higher affect. Their plan put South Carolina — the state that revived Mr. Biden’s flagging 2020 marketing campaign — first and would have pushed New Hampshire to second, alongside Nevada.

However New Hampshire Democrats, who delight themselves on the state’s longtime first-in-the-nation custom — a matter of state law — balked, and the state was stripped of its delegates.

Finally, main Democrats within the state put apart their vociferous criticism of the calendar overhaul to again the top of their celebration, at the same time as they staunchly defended their major custom.

“It’s in our D.N.A. — it’s part of who we are,” former Gov. John Lynch mentioned. “But also, I think there are Democrats, myself included, who are willing to sort of step back and say, you know, What’s the bigger picture?”

Ms. Sullivan, a frontrunner of the write-in marketing campaign, mentioned that there have been essential classes from that effort that the nationwide celebration might be taught, particularly on the subject of empowering grass-roots supporters.

Requested if she supposed to share these conclusions with the Biden marketing campaign, she replied, “If they’re interested in talking to us.”

“We’re here if they want to talk,” she laughed.

Nick Corasaniti and Anjali Huynh contributed reporting from Manchester, N.H., and Chris Cameron contributed reporting from Harmony, N.H.