OLYMPIA, WASH. ? After three vote tallies and nearly two nerve-racking months of waiting, Democrat Christine Gregoire was declared Washington’s governor-elect Thursday. 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 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 the Legislature.

Rossi and the state GOP said they had 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 ultraclose 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 from his campaign headquarters.

Gregoire congratulated 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” occur only 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 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 129 votes out of more than 2.8 million cast.

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

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

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

Rossi said the Legislature should authorize a new election.