There are 5 refineries in Washington running a total of 613,150 Barrels Per Day. All but ~10% of that oil is already supplied by North American sources, mostly Alaska. So they import from overseas ~60,000 BPD.
http://www.commerce.wa.gov/_CTED/documents/ID_2921_Publications.pdf
What would they do with another 710,000 BPD?
It would also be a hell of a lot shorter.
It would also cross the Rocky Mountains. You can cross a lot of miles of flat land for the cost of a mile through the Rocky Mountains.
The Gulf Coast area refineries import millions of barrels per day of oil from overseas. We could use the existing refineries, with the existing gasoline, diesel, etc distribution pipelines by just replacing some of the imported oil and extending one crude oil pipeline.
Do you know how many really fun conspiracy theories have been ruined by you and your actual facts?