my question is why has the state shifted to the democrats so much at the presidential level? In my 1974 Almanac of American Politics, a full 56% of the voters were registered democrats. Now its down to 44%. The number of DTS voters has also increased from 7% in the 1970s to the current 26%.
One thing someone on redracinghorses said was that California democrats are much more partisan now then they were back then and that Reagan always enjoyed support in heavily democratic areas (by registration) such as Bell Gardens, Huntington Park, El Monte etc.
As Xahar said, partisan affiliation isn't particularly meaningful at the presidential level (just look at Oklahoma
) And yes, Reagan did well among the blue-collar white Democrats in places like the ones you mentioned-though it must be remembered, of course, that it was the white-collar middle and upper class areas of the state (Orange County being the classic example) that were historically always the most strongly Republican, and where the grassroots 'movement conservatives" of the Goldwater campaign (and later the Reagan campaign) were most concentrated.
Furthermore, the Reagan effect was real everywhere, but in California it masked the underlying trends towards the Democrats. Bush Sr kept CA in the GOP column in 88, but he was no match for the charismatic, culturally progressive, economically center-right reformist "New Democrat" Bill Clinton in 92-and those Third Way qualities played well in California.
Finally, demographic changes in the California electorate played a big role, of course. California's Democratic Party is very diverse, with so-called "gentry liberals", young professionals, blue-collar Latino workers, public sector employees, Silicon Valley executives, naturalized Asian immigrants, Hollywood executives, San Francisco bankers...all of these people find common cause with the Democratic Party.
It helps the Democrats, btw, that both the California Republicans and the national Republicans have become increasingly right-wing, partisan, and ideologically rigid. As California becomes ever more diverse, cosmopolitan, and urban/metropolitan-focused, what plays well in more homogenous suburbs and exurbs of "Middle America" falls flat on its face here, politically speaking.