WASHINGTON — In a win for Republicans, the Supreme Court said Thursday that student IDs cannot be used in New Hampshire for the midterm elections .

The justices granted an emergency request filed by the state, which had the backing of the Republican National Committee.

The ballot in New Hampshire includes a closely watched Senate race that could play a key role in deciding control of the chamber. Republican former Sen. John E. Sununu is pitted against Democratic Rep. Chris Pappas for the seat held by retiring Democratic Sen. Jeanne Shaheen.

The brief court order said a federal judge should not have ordered a change in voting rules so close to the Nov.…