[thesmallestcat]

Mostly because no cost would be seen as too high for maintaining access to the Pacific. Also, the Pacific Coast and Sierra Nevada range are crucial elements of US defense strategy. The US also has some substantial military bases and accompanying sympathetic populations in CA, especially in the San Diego area.

[crucini]

Seems like these problems are solvable. Give the USA some corridors to the Pacific, going through low density areas. Keep the military bases and a unified defense strategy; California can pay USA for defense. US has military bases in lots of countries; why not in California?

https://en.wikipedia.org/wiki/Polish_Corridor