Well, this might be potentially competitive. I have heard that Dave Reichert, a moderate republican representative, might seek this seat in 2016.
They already tried running a popular Republican Congressman against her in a Presidential year.
Reichert is from King County though, so he'd probably do better than Nethercutt.
To qualify, it's a very small, working-class suburban/rural conservative-leaning corner of King County. The swingy suburbs were all drawn out of his district post-2010 and his district includes a lot of the central part of the state now. (He used to be my Congressman). I wouldn't be surprised if he ran, though, and he'd still do better than Nethercutt. If he vacates, his seat could be a D reach with the right conditions and candidate.
