Republicans have already agreed to their own early-state lineup of Iowa, New Hampshire, South Carolina and Nevada.
The Rules and Bylaws committee’s vote came a day after Mr. Biden sent a letter to members laying out his criteria for the early-voting window. In it, he rejected caucuses — effectively dealing a mortal blow to the troubled Iowa caucuses, which struggled for days to deliver results in 2020.
After Mr. Biden came in fourth place in Iowa and fifth in New Hampshire, two states with high percentages of white voters, he showed new signs of political life in Nevada. And it was South Carolina’s primary, with large numbers of Black voters, that revived his candidacy and propelled him through Super Tuesday and to the nomination.
“Defense, education, agriculture, manufacturing — South Carolina is a perfect laboratory,” said Representative James E. Clyburn, the South Carolina Democrat whose endorsement of Mr. Biden in 2020 played a vital role in the president’s victory in the state. “That’s why the people who do well in South Carolina end up doing pretty good in the general.”
Mr. Clyburn said that he had urged Mr. Biden to keep South Carolina in the early-state window — “first, second, third or fourth, didn’t matter to me” — but that he had learned of the state’s possible elevation to the kickoff primary on Thursday from the president.
Jaime Harrison, the chairman of the D.N.C., who is also from South Carolina, said he had found out at Thursday night’s state dinner.
Mr. Biden has urged the Rules and Bylaws Committee to review the calendar every four years, and the committee embraced an amendment to get that process underway.
“Nevada still has the strongest argument for being the first-in-the-nation primary,” Catherine Cortez Masto and Jacky Rosen, the state’s senators, said in a joint statement. “We will keep making our case for 2028.”
Reid J. Epstein contributed reporting from New Orleans, Lisa Lerer from New York, and Trip Gabriel from Des Moines.
