WASHINGTON  Senate Republicans on Wednesday forced a one-week delay in a vote on the nomination of Eric H. Holder Jr. as attorney general, denying President Obama the chance to have a key member of his national security team in place as planned.

Mr. Holder’s ultimate confirmation still appears all but assured. But the procedural delay led Democrats and Republicans on the Senate Judiciary Committee to accuse each other of souring the spirit of bipartisanship that Mr. Obama’s inauguration was supposed to signal.

Senator Arlen Specter of Pennsylvania, the ranking Republican on the committee, has led the opposition to Mr. Holder’s nomination.

Mr. Specter said Wednesday that Republicans had been denied the time to raise important questions, a charge that his Democratic counterparts deny.