Sen. Patty Murray (Creative Commons)

AP has projected that incumbent Democratic Sen. Patty Murray will win the long, difficult race with Republican challenger Dino Rossi.

Pivotal to Murray's victory is King County, where Seattle is located. The King County votes have favored Murray, and she now leads Rossi by more than 45,000 votes--up from 14,000 on Election Day.

The Seattle Times reports: "To overcome King County's heavy support for Murray, Rossi would have to take about two-thirds of the remaining ballots in the rest of the state. So far he's received 53.2 percent of those non-King County votes."

Rossi had reason for hope earlier Thursday.

"It's guesswork. We need to see more results. Really, that's the bottom line," Rossi's campaign manager, Pat Shortridge said earlier. "There are a lot of ballots out there, and we've got to count them."

Rossi has been performing better this year in Eastern and Southwest Washington than he did in 2004 when he lost the closest gubernatorial election in history to Gov. Christine Gregoire. However, he has less votes in the more liberal areas, like King County, than in the 2004 election.

By Tuesday evening, it was clear which way King County was taking the race.

Reach reporter Monica Nguyen here.