As Rob McKenna, a Republican, battles his Democratic rival, Jay Inslee, for Washington's governorship, state Republicans are also waging a lower-profile but more difficult campaign to wrest control of the state Senate.

Republicans would need to pick up three Senate seats to regain control of the chamber, which has been in Democratic hands since 2005. Democrats have held the House since 2002 and scoff at any Republican talk of taking control in November, for which the GOP would need to gain eight seats. The current breakdown in the House is 56 Democrats and 42 Republicans.

The Aug. 7 primary election will give both parties an idea of how they're doing. It will also winnow down three- and four-way races in which Democrats or Republicans are clawing at each other for a seat.

Twenty-four of the 49 seats in the Senate are on the ballot this year, but the fight for control of the chamber may come down to a few key races in swing districts of Western Washington.

Republicans are targeting three seats in particular, said Kirby Wilbur, chairman of the state Republican Party: those of the 1st District, which includes Bothell and Mountlake Terrace and straddles Snohomish and King counties; the 10th District, taking in Whidbey and Camano islands and swaths of Skagit and Snohomish counties; and the 25th District, centered on Puyallup.

The hottest of those races is likely in the 1st District. Sen. Rosemary McAuliffe, a Democrat from Bothell who has held the seat for 20 years, is facing Dawn McCravey, a Republican, and Guy Palumbo, a Democrat. Under Washington's "top two" primary system, the two candidates with the most votes move to November's general election, regardless of party affiliation.

Palumbo, 38, a former Amazon worker who owns a dog-boarding business in Snohomish County, has out-raised his opponents, collecting $71,153 in donations, according to the Public Disclosure Commission.

He criticizes McAuliffe, chairwoman of the Senate's education committee, as too close to the Washington Education Association. (The WEA has raised $43,600 in independent money to support McAuliffe; she has raised $60,394 on her own.) Palumbo casts himself as a more independent-minded alternative on issues such as education and regulation. He supports charter schools, for instance.

McCravey, 56, who sits on the Northshore School Board, has also tried to claim the upper hand on education, which has emerged as a signature issue around the state. She faults McAuliffe for not getting a bill on charter schools out of committee.

But McAuliffe, 71, who won 58 percent of the vote in her last election in 2008, seems sanguine about her first three-way race. "I have a 20-year record that speaks for itself," she said.

Republicans are also eyeing the Senate seat in the 10th District, where the Democratic incumbent, Mary Margaret Haugen, faces a challenge from Barbara Bailey, a House Republican.

It's far from certain that Republicans will be able to hold all their Senate seats, particularly in the 5th District in East King County, where Sen. Cheryl Pflug's decision in May to accept a position on the Washington Growth Management Hearings Board left the GOP scrambling. Sen. Ed Murray, co-chairman of the Senate Democratic Campaign Committee, said he thinks Democrats can take Pflug's seat and fend off Republican challenges in the 1st and 10th districts.

The battle for the House may be less competitive.

Next week's primary will knock out candidates in a number of crowded races for solidly Democratic seats in Seattle. A race in the 11th District, which stretches from South Seattle down to Renton, has drawn four Democrats and a Republican. Another in the 36th District, which takes in Ballard, Magnolia and Queen Anne, has seven candidates, mostly Democrats. And one seat in the 46th District, in the city's northeast, has six candidates running, four of whom are Democrats. Those three contests are all for open seats.

Christian Sinderman, a Democratic political consultant, said Republicans might pick up a couple of House seats — in the 28th, for instance, in Pierce County — but that the chamber is unlikely to flip. "No one is really predicting that the House will change," he said.

The Senate may be a different story. "I would say it's going to be very close," said Bruce Dammeier, a popular Republican running for the Senate in the 25th. "Regardless of who's in control, every policy's going to receive bipartisan scrutiny."

Theodoric Meyer: 206-464-2985 or tmeyer@seattletimes.com. Twitter: @theodoricmeyer.

Information in this article, originally published July 30, 2012, was corrected July 31, 2012. A previous version of this story misstated the party affiliations of candidates running for a 46th District seat in the state House of Representatives. Four are Democrats, one is a Republican and one prefers the Democratic-Repub Party.