Snohomish County Councilman John Koster, the lone Republican on the council, has set his sights on a nationwide target-the 2nd District congressional seat currently held by Democrat Rep. Rick Larsen.

The matchup is not a new one. Larsen and Koster vied for the U.S. House of Representatives position in 2000, with Larsen the winner. Koster, who was recently re-elected to the county council for his third and final term, thinks the time is right to throw his hat into the ring again.

In press releases and his Web site, Koster draws a sharp contrast between his "steady conservative political approach to that of the 'progressive' socialist agenda of the incumbent."

Larsen has not addressed the challenge directly, but his staff said the congressman "looks forward to a spirited debate" in the months ahead.

The differences between the two politicos are stark. The National Republican Congressional Committee, which backs Koster, has criticized Larsen's "anti-jobs big government agenda."

In a release that previews the tone of the challenger's campaign, Koster claims, "Rick Larsen offers Washingtonians a failed socialist ideology that punishes prosperity and produces mediocrity. Government cannot spend us into prosperity."

Last summer, as Larsen's colleagues faced hostile crowds, the congressman presided over a peaceful town hall meeting on the health care issue that drew 8,000 people to Everett Memorial Stadium.

He worked to win concessions for oil refineries in the energy and climate bill that narrowly passed in the House last summer, and he won improved staffing and security at the U.S.-Canada border. Larsen was also a principal architect of legislation creating the 106,000-acre Wild Sky Wilderness Area in eastern Snohomish County.

The two candidates, along with any others who may file for the seat, will appear on the August 17 primary ballot.

Koster is a former dairy farmer who served three terms in the Washington State House of Representatives before diving into local politics. His current tenure on the county council ends in 2013, and term limits mean he won't be able to run again.

The 2nd Congressional District covers most of Snohomish County along with all of Island, San Juan, Skagit and Whatcom counties.

Larsen won the 2000 contest over Koster by about 12,000 votes, although Koster had the lead following the primary that year. The two candidates raised and spent comparable contributions, $1.5 million for Larsen and $1.1 million for Koster.

In 2008, Larsen easily eclipsed challenger Rick Bart for the seat.