So the East/West divide was already there in the 60s? I'd have thought the Democrats were much stronger in the east at that time.
Eastern Washington did elect democrats to congress for prolongued periods of time. Spokane area was represented by Tom Foley and the Tri Cities was represented by Mike McCormack for a few years in the 70s. That was probably in spite of their partisan affiliation and not because of it. Kind of like how Nebraska for 30 odd years had at least one dem senator (and even had two at one point)
