Oregon vs Washington

[clever but short]

Why in presidential elections was Oregon consistently slightly more Democratic than Washington, and now consistently slightly more Republican? Oregon was to the left of Washington for most of the 1970s and 1980s, with 84 being an exception. Then in the 1990s they appear to have switched positions.

Results in 1950s and 1960s are somewhat less regular, although for most of the 50s Oregon was to the right and for most of the 60s Oregon was to the left. The notable exception is 68, when Humphrey won Washington but not Oregon.

[OSR stands with Israel]

The Suburbs even in the North were a keystone to Republican success in the 1970s and especially the 1980s and Washington being a much more suburban state than Oregon made Washington more Republican overall. Oregon metros compared to Washington metros were nowhere near as suburbanized and that made Oregon slightly more Democratic than Washington

In the 1950s and 1960s the suburbs weren't as dominant as they would become in the 1970s and 1980s made it so that Oregon being a more rural state made Oregon a more Republican state and since the 1990s the suburbs in Oregon and Washington going Democratic once again made the fact that Oregon is a more rural state than Washington more Republican as well

[Roblox]

Probably has to do with the Seattle metro containing a much larger share of Washington's population than Portland in Oregon.

[Sumner 1868]

Oregon didn't have anywhere near the level of Scandinavian immigration Washington did at the turn of the 20th century. This is probably the main reason why Oregon has consistently been on the right of Washington.

[Ogre Mage]

Why in presidential elections was Oregon consistently slightly more Democratic than Washington, and now consistently slightly more Republican? Oregon was to the left of Washington for most of the 1970s and 1980s, with 84 being an exception. Then in the 1990s they appear to have switched positions.

Results in 1950s and 1960s are somewhat less regular, although for most of the 50s Oregon was to the right and for most of the 60s Oregon was to the left. The notable exception is 68, when Humphrey won Washington but not Oregon.

A great deal of it has to do with major population growth which occurred in Seattle from 1990 on.  Also, the Eastside suburbs of Seattle -- Bellevue, Redmond, Kirkland, etc. -- shifted from being strong country club Republican territory to Democratic during this period.  The Eastside also experienced significant population growth.  

Probably the clearest sign the balance of power had shifted was Maria Cantwell's razor-thin victory over then-Sen. Slate Gorton in 2000.  Gorton was a three-term U.S. Senator infamous for running against King County and especially Seattle.  He portrayed Seattle as the worst excesses of left-wing radicalism.  Cantwell only won 5 counties and primarily owed her victory to an overwhelming margin in King County.