President Biden will win the New Hampshire Democratic primary on Tuesday, AP projects, fueled by a write-in campaign.

Why it matters: Although he does not win any delegates, it's a big win for Biden as he seeks to boost enthusiasm surrounding his re-election bid.

• The Biden write-in effort, unaffiliated with the official campaign, edged out Democrats including Marianne Williamson and Rep. Dean Phillips (Minn.), who appeared on the ballot.

The big picture: Biden's campaign said last year that he would not file to have his name on the New Hampshire primary ballot to comply with the calendar set by the Democratic National Committee.

• The DNC made South Carolina the nation's first primary state, a move that Biden backed to give states with more diverse populations more of a say in early presidential contests.

Zoom in: New Hampshire still went ahead with its primary to preserve its first-in-the-nation status, despite the DNC saying that a win there would not count toward the candidates' delegate totals.

• "New Hampshire has held the first-in-the-nation presidential primary election for over 100 years," New Hampshire Secretary of State David Scanlan said in November. "And we will vigorously defend it."

What to watch: The South Carolina Democratic primary, scheduled for Feb. 3, is the first official Democratic primary of 2024.

• Biden has descended on South Carolina for campaign events to try to boost turnout and enthusiasm surrounding his re-election bid.

Go deeper: Biden campaign plots late push ahead of South Carolina primary