The Washington Senate race is considered to be extremely important because the control of the Senate could hinge on its outcome. It is hard to envision a scenario in which the GOP gets 51 seats in the Senate without picking up Washington. The latest SurveyUSA poll shows the race still statistically tied, with incumbent Democrat Patty Murray holding a three point edge over Dino Rossi.

SurveyUSA (10/11-14)
Patty Murray (D) 50
Dino Rossi (R) 47
Undecided 3

The race is effectively unchanged since the last time SurveyUSA polled three weeks ago.

This poll, though, is wildly different from a recent Elway Poll, which had Murray leading by 15 points. What accounts for the huge divergence in polling? Nate Silver noticed that SurveyUSA  tends to have a slightly Republican bias in its Washington State polling, and Elway tends to have a slight Democratic bias. I suspect the final result will probably end up somewhere in between these two polls.

Both candidates are well known, Rossi has previously, unsuccessfully run for statewide office–twice–and there havn’t been any big surprises this cycle. Since Washington State already tends to have very high midterm turnout, I don’t think the enthusiasm gap will have a big effect in the state. Given that, I think my analysis from the top-two primary results indicating Murray will eventually win by single digits will probably be correct.