President Joe Biden will not file for New Hampshire's Democratic primary because he is "obligated" to comply with the Democratic National Committee's delegate selection rules, his campaign manager informed the state party in a letter obtained by CNN.

Under a Biden-backed plan approved by the DNC earlier this year, South Carolina -- and not New Hampshire -- will be the first state to hold an approved Democratic primary.

Even though New Hampshire's primary date has not yet been set, Secretary of State David Scanlan has already said his state will hold the first-in-the-nation primary. That will make it non-compliant with the new DNC calendar, which could cost New Hampshire Democrats party delegates to the national convention next summer.

The president would like to participate in the Granite State primary, campaign manager Julie Chavez Rodriguez wrote to New Hampshire Democratic Chairman Ray Buckley, but he must comply with national party rules.

It would be a violation for Biden to campaign in such an early contest in New Hampshire or to even have his name on the ballot, although voters could write him in.

"The president is incredibly grateful for the support that Granite Staters have shown him both as a candidate for office and as president of the United States," Chavez Rodriguez wrote.

Buckley responded Tuesday in a statement, saying, "The reality is that Joe Biden will win the New Hampshire First-in-the-Nation Primary in January, win renomination in Chicago and will be re-elected next November." He continued: "New Hampshire voters know and trust Joe Biden," he added.

The New Hampshire Republican Party said on X, "Joe Biden doesn't care about the granite state, our traditions, or our voters."