Republican Dino Rossi (search) and the state GOP announced Friday they will contest the gubernatorial election that gave his Democratic foe, Christine Gregoire (search), a 129-vote victory.

Republicans have been building a case over the past few weeks, gathering evidence of voting irregularities, including illegal provisional ballots and a handful of votes cast by dead people. They are pushing for a revote, an unprecedented step in a statewide election.

"There are so many improperly cast and counted ballots that this election is invalid," Rossi said. "You cannot tell who won. The only way for us to get out of this problem is for us to have a revote."

Gregoire, a three-term attorney general, lost the first count by 261 votes to Rossi, a real estate agent and former state senator. Rossi won a machine recount by 42 votes but lost a hand recount of 2.9 million ballots.

Gregoire, whose inauguration is scheduled for Wednesday, has called the idea of a revote "absolutely ludicrous" but acknowledged Rossi's right to contest the election.

"I don't take any of this personally," she told a news conference in Olympia. "I respect the right of others to file an action in the courts. That is their right."

GOP attorney Harry Korrell said Republicans would not seek to block Gregoire's inauguration, but the party planned to immediately file a lawsuit contesting the election in Chelan County (search), in north-central Washington.

Democratic lawyers said an election challenge is unfounded and the state constitution will not allow a revote.

"No court will find this election should be set aside," Democratic Party attorney Jenny Durkan said. Even if illegal votes were cast, she said, "it would not change the outcome of the election."

Durkan said the constitution requires that the governor be chosen in the same election as state legislators and only in a November general election. She said a revote would first require a statewide vote on changing the state constitution next November and then an election in November 2006.

Former U.S. Sen. Slade Gorton (search), a Republican supporter of Rossi, said he believes the GOP has enough evidence to support an election challenge. He pointed to questions about mishandled provisional ballots in King County.

Gorton acknowledged there was "no serious allegation of someone doing this deliberately or fraudulently" but said that does not matter. If enough illegal votes were cast for any reason, he said, the election results must be set aside.

"If it comes to that, it is better to have the electorate, not the court or the Legislature, decide," Gorton said.

GOP observers say hundreds, perhaps thousands, of King County provisional ballots were fed directly into vote-counting machines on Election Day, when staffers should have verified that they belonged to registered voters.

Any election challenge will certainly end up before the state Supreme Court.

Supreme Court Clerk C.J. Merritt said the court will wait until the filing period closes before deciding what to do with election challenges. The deadline is 10 days after the Legislature issues a certificate of election, which is expected to happen Tuesday.

The Seattle Times and the Seattle Post-Intelligencer reported Friday that some people who died before absentee ballots were mailed had been credited with voting in the November election.

The Times found 24 examples of deceased voters in six of the state's largest counties. The Post-Intelligencer found eight such examples in King County alone.