The 26th District race between Democrat Nathan Schlicher and Republican challenger Jan Angel has already seen a combined spending of $1.9 million, with about half of that money being spent by third-party groups.
Schlicher, an emergency room doctor from Gig Harbor, was appointed to the Senate seat in January to replace Democrat Derek Kilmer, who was elected to Congress. Angel, of Port Orchard, has served in the House since 2009.
Both currently represent the district they are vying for, a swing district that includes the southeastern Kitsap peninsula from Bremerton and Port Orchard to Gig Harbor in Pierce County.
A predominantly Republican Majority Coalition Caucus controls the Senate with the help of two Democrats, giving the majority caucus a one-vote advantage in the chamber. Republicans would like to increase the cushion of their hold of the upper chamber heading into the 2014 elections that will see half of the Senate up for re-election.
"The stakes are very, very high this year," said University of Washington political science professor Matt Barreto.
Angel's spokesman said she wasn't giving any more media interviews between now and next month's election. But he noted that she's been elected by voters in the district three times, most recently with 59 percent of the vote.
"She's clearly in step with her district, and they've reaffirmed that several times," he said.
Angel, 66, previously worked in business and real estate and served as a Kitsap County Commissioner for eight years.
Schlicher, 30, graduated from high school at 14, has both law and medical degrees and works six days a month in the emergency room at St. Joseph Medical Center in Tacoma.
He describes himself as a "moderate at my core."
"I try to really look at the issues, I try not to look at the partisanship," he said.
Combined, the two candidates have spent more than $950,000 in the campaign, but third party spending has topped $1 million, with more than half of that being spent in opposition of Angel.
Thomas Steyer, a California environmentalist, has put $6.3 million into NextGen Climate Action Committee, a political action committee set up in Washington state. NextGen has given $250,000 to one political action committee that supports Schlicher, and has given another $150,000 to another committee, Washington Conservation Voters, that has donated to the committee that is attacking Angel.
Matthew Lewis, a spokesman for NextGen, noted that the committee is involved in races around the country, including the governor's race in Virginia.
As for the interest in Washington state, he said the committee has an interest in efforts taken by states on climate issues.
"States have to take a proactive role in making the transition to a clean energy future," Lewis said.
Angel has also benefited from out-of-state money, including $115,000 in donations from a national Republican group to one committee that is putting money in another committee that is spending money to attack Schlicher.
Previously, the most expensive legislative race was the 2012 Senate contest between Tacoma trial lawyer Jack Connelly and then-state Rep. Jeannie Darneille. Connelly spent almost $1 million of his own money, and $1.3 million overall was spent in the race that was ultimately won by Darneille.
Two other Senate races are on next month's ballot. In the 7th District, Republican Sen. John Smith of Colville, who was appointed in January to succeed retiring state Sen. Bob Morton, faces fellow Republican Brian Dansel, and the in the 8th District Republican Sen. Sharon Brown of Kennewick, who was appointed in January to replace Sen. Jerome Delvin, is running against Republican Phillip R. Lemley.