OLYMPIA, Wash. (AP) - After four years of anticipation, months of negative ads and weeks of legal maneuvering, the rematch between Gov. Chris Gregoire and Republican Dino Rossi comes to a close this week.

Voters have been casting their votes since mid-October, and while early results will start trickling in on Tuesday night, the final determination of who has won this long, drawn-out battle likely won't be known for days, if not longer.

"If it ends up being a cliffhanger again, the ghost of '04 comes back and the Republicans will fight harder and not concede as easily," said Cornell Clayton, professor of political science at Washington State University.

The governor's race is the marquee contest on a Washington state ballot that also includes other statewide executive offices, seats in Congress and the Legislature, and ballot initiatives on assisted suicide and traffic congestion. At the top of the ticket, Democrat Barack Obama is favored to carry Washington's 12 electoral votes in his battle with Republican John McCain for the White House.

Gregoire, a former state attorney general, won the 2004 contest by the closest percentage margin of any governor's race in U.S. history - just 133 votes out of about 2.8 million cast.

She got that slim margin only after two recounts, and the victory wasn't even final until the following summer, when Republicans lost a courtroom challenge.

The sting of that loss has been simmering within Republicans for four years, and was inflamed by a deposition of Rossi just six days before the election. Rossi was questioned for a lawsuit that accuses the Building Industry Association of Washington - Rossi's biggest backer - of illegally raising money for his campaign.

That latest twist turned up the dial even more on what had already been a contentious race.

"It's been a pretty hard-hitting race all along, and it's widely perceived to be very close, so that always engenders less restraint," said independent pollster Stuart Elway.

For Democrats, "losing the governor's race, the stakes here are just enormous," said Chris Vance, a Republican political consultant and former state party chairman who supports Rossi. "In terms of Washington state politics, it just does not get bigger than this."

Rossi and Gregoire have raised more than $20 million combined in the most expensive election in Washington history. That amount doesn't include the millions spent by third-party groups on TV ads and mailers, most of them negative in tone.

The state economy, along with a projected $3.2 billion deficit, and the issue of taxes has dominated the race, with both candidates hammering on those issues in ads and five debates.

The next governor and Legislature will have to solve the budget hole starting in January. Gregoire has said she will do it without taxes, but Rossi has insisted that he's the only candidate who can steer a no-tax budget.

Even though voters have until midnight Tuesday to either drop off their ballots or get them postmarked and mailed, they may have already tuned out the back-to-back TV ads that have blanketed the airwaves in the past few weeks.

"We're in saturation mode right now, people are just trying to escape it," said Cathy Allen, a Democratic political strategist and Gregoire supporter. "The public is like 'we don't want to hear any more'."

But while they may be tired of the politicking that goes on in campaigns, officials note that it hasn't slowed down the number of ballots already arriving at county auditor offices.

Coupled with the presidential race, interest in the governor's race is why Secretary of State Sam Reed is predicting near record turnout.

"People are really passionate," Reed said. "I think we're going to have a robust turnout."

Reed expects an 83 percent turnout statewide - about 3 million people - with some counties expecting their individual turnout numbers to be even higher.

With the surge in new voter registrations and high turnout, some worry about a repeat of the extended 2004 election between Gregoire and Rossi. Polls show Gregoire and Rossi running very close again, all but ensuring that the race will be unresolved on Election Night.

Smaller counties, including those in conservative rural areas, will likely get their votes counted faster, which could lead to a repeat of 2004, when Rossi was ahead on Election Night, but watched his lead dwindle as the vote was counted in greater Seattle. He was ahead in the final vote by 261 votes, but a machine recount narrowed the lead to just 42 votes before the hand recount put Gregoire ahead.

On the other hand, Gregoire had a solid lead at the end of this year's primary night, ahead by about 4 percent. By the time all the votes were counted and certified, that lead dwindled to less than 2 percent.

"It all depends on the margin of victory," Clayton said. "If Gregoire wins by a comfortable margin, say 2 percentage points or more, then that puts to rest the last election. On the other hand, if it's a more narrow lead, or Rossi wins by a small margin, there will be a lot of bitter feelings."