Why did CA, IL, NJ, CT, and VT vote Republican before 1992?

[Mr. Smith]

CA was always a swing state after JFK opened it up.

Part I:

But Nixon was a native son which just barely got him over the line with Humphrey, Carter was a bad fit [Frank Church, Scoop Jackson, or Jerry Brown could've overcome the Orange County meter by flipping then Rocky GOP county Contra Costa and solidifying the Dixie Inland].

Part II:

Reagan managed to flip over a lot of the Dixie North that were Solid D thanks to the Water Wars, while the Rocky GOP parts of the Bay Area, like Vermont...were still glacially moving over.

But Dukakis, while an excellent fit, ran a horrible campaign.

Moral of the Story: Should've given the South the middle finger and nominated a liberal and competent Westerner with an environmental streak and no taste for war.  LBJ was the only one who ran on any sort of Western cred.

[Mr. Smith]

Why California left the Republican Party (for good)? Two words: Religious Right.

It's actually quite sad...I do not like that California has become a one party state. I do not think that it is good for democracy, but the Republican party needs to transform into a European-style conservative party in order to become competitive in California again.

That's why it really trended away. But the shift would've come a lot sooner if the correct type of Democrat for the state took the nomination.

P.S. The Dixie North/Gold Country counties became more Republican because of that same element.