The question is going to be asked this year: Are Washington and Oregon one-party states? Actually, it's already being asked; a David Brewster piece in Crosscut already asks it (and wrestles with but doesn't totally pin it).
Let's define some terms.
A one-party state is where one party is in near-total dominance, and the other is reduced to virtual non-competitive status. Look at Idaho, where statewide Republican candidates nearly always win in landslides or near-landslides, and where the legislature is upwards of 80% Republican. That's a one-party Republican state.
Not so far from that is California, at least after last week's election. There, Democrats dominate among the statewides and will hold two-thirds of the state's legislative seats. Such gaudy margins may or may not hold, but that has the look - for now anyway - of a one-party Democratic state.
Washington and Oregon are something else.
Democrats do have a definite advantage in them; these states are closer to blue than to red.
They have all the partisan statewide offices in Oregon, and all but one in Washington. They have both U.S. Senate seats. They have control (after this year's election) of both legislative chambers in each state.
But we can't really use the same kind of overwhelming language to describe them.
In Oregon, Democratic Governor John Kitzhaber just barely won in 2010. Republicans do have a U.S. House seat (one of five). The Democratic majority in the Senate amounts to a seat seat above tie, and in the House, which just emerged from a tie, Democrats have a fragile four-seat advantage, which could melt away again as swiftly as it returned this year.
In Washington, Republicans hold four of the 10 U.S. House seats, a point often forgotten after the loss of three open-seat races this time (two of those in districts where the Democratic voter edge is strong anyway). And while they remain a legislative majority, the margins are close enough to put Democratic control in regular jeopardy - and may be in the next session amid semi-revolt from a couple of the caucus members.
Put Washington and Oregon in a different cetegory - Democratic-leaning, but not one-party.