State Sen. Michael Baumgartner is challenging Sen. Maria Cantwell (Wash.) next year, becoming the first Republican to enter the race against the two-term Democrat.

Should he win the nomination, Baumgartner would have a tough road to victory hailing from the less populous eastern portion of the state and with recent history on the Democrats’ side.

Sen. Patty Murray (D) brushed off a GOP challenger by 5 points last year in a strong cycle for Republicans.

Whatever the matchup is in November 2012, it will take a back seat to the high-profile gubernatorial contest between Attorney General Rob McKenna (R) and Rep. Jay Inslee (D).