OLYMPIA, Wash. – After three vote tallies and nearly two nerve-racking months of waiting, Democrat Christine Gregoire was declared Washington’s governor-elect yesterday. But her Republican rival did not concede and wants a new election.

“Less than two weeks from today I will take the oath of office as your next governor of the great state of Washington,” an ebullient Ms. Gregoire told supporters at a Capitol news conference.

The Republican candidate, Dino Rossi, said he was exploring whether to contest the election in the courts or in the Legislature.

Mr. Rossi and the state GOP said they have discovered a discrepancy of more than 3,500 votes in strongly Democratic King County, the state’s largest, possibly pointing to fraud or mistakes that could have swung the ultra-close election.

“I think we need to examine what’s right and what’s wrong and let’s expose it and see if we can correct it,” he said at a news conference from his campaign headquarters.

Ms. Gregoire congratulated Mr. Rossi for running a strong campaign, and said it was up to him to decide when and where to concede. But she ruled out a brand new election.

“Do-overs” only occur in golf, and only during practice, she said. “This is not golf and this is not practice.”

Secretary of State Sam Reed, a Republican, certified Ms. Gregoire, the three-term attorney general, as the winner of the closest governor’s race in state history. She won a statewide hand recount by a scant 129 votes out of more than 2.8 million cast.

Mr. Rossi won both of the earlier counts – the initial tally following the election and a statewide machine recount.

While there were mistakes, Mr. Reed told a news conference, “at this time there is nothing that appears fraudulent.”

“I saw serious mistakes being made. I saw them being corrected,” Mr. Reed said. “That’s part of the process. The system itself has worked well.”

Mr. Rossi, a former state legislative leader and real-estate investor, said the election was hopelessly flawed and that the Legislature should authorize a new election.

While noting that he could contest the election, Mr. Rossi said a legal challenge could drag on for months. The better way to clear up the mess, he said, would be to ask lawmakers to pass a bill calling for a special election as soon as the state Legislature convenes in early January for the 2005 session.

After the election, more than 700 ballots surfaced in King County, which includes Seattle. The additional votes allowed Ms. Gregoire to stretch her lead from just 10 votes in the hand recount to her triple-digit advantage. A legal challenge would have to be filed by January 22, 10 days after Ms. Gregoire’s scheduled inauguration.