Why is Oregon more Republican than Washington?

[ottermax]

Coming from WA and knowing it quite well, I have always known that the West side is liberal and more populated with pockets of rural and suburban conservatism. The East is conservative all around with tiny pockets of immigrant liberalism and urban voters.

The one thing about WA is that even without suburban GOP support they can always rely on a substantial Eastern WA rural support group.

Driving through Oregon a few weeks ago I realized that Eastern Oregon is empty - Bend is really quite small and the largest city. Oregon only has 1 Republican representative, but 4 Democrats, while WA is a 6-4 split. Driving through the Willamette valley it appears that there are more rural, conservative voters here, but still not a ton.

So I guess my question is what about Oregon makes it more conservative than Washington? A smaller urban population? A larger rural population? A more conservative suburban area? Fewer minorities? None of it makes much sense to me, but the numbers are clear. Any thoughts or theories?

[ottermax]

There's like 1 point between them.

It's a consistent trend though.

It's clear that SW Oregon is somewhat more conservative than SW WA, along with E OR vs E WA, but when looking at the actually populations these rural areas can't be the full reason. It seems that the Portland metro is more conservative, but why?