My opinion is that the CA Republican Party was destroyed mainly by Jerry Brown, Phillip Burton, Rose Bird, Willie Brown, and Tony Coehlo. Jerry Brown stacked the state judiciary with leftist, hyper-political judges who reflexively supported Democrats regardless of merit. Rose Bird was the most flagrant of them. Phillip Burton’s redistricting plan, with input from Coehlo and Willie Brown, locked Democrats into majorities which couldn’t be dislodged, even when they lost the majority of the vote. So even when Republicans elected governors, their power was limited. The end result was that Republican, conservative, and religious voters moved away in droves to get away from the inevitable result of leftist governance. That demographic change has also contributed to California’s budgetary problems.
Dishonorable mention goes to Ross Johnson, the Assembly Minority Leader who insisted on having lousy candidates running in marginal districts, effectively handing them to Democrat nominees by default.
The Democrats can only do so much from without... it’s the damage of incompetent leadership (the establishment RINOs wishing to just be the pale copy of the Democrats) within the party most responsible.
The more I research and think on it, Republican incompetence (lousy leadership, candidates, ideology) are almost solely to blame for so many Democrat successes. Look at the last 5+ decades in the state. Had a Republican Governor been in place for redistricting in 1962, it would’ve stymied the Democrat shift (hence no Pat Brown). No Watergate/ITT Scandal, a Republican would’ve succeeded Reagan in 1974 (no Jerry Brown).
This would’ve been 3 key successive points where a GOP Governor combined with a legislature would’ve presented us with a far different set of Congressional lines (indeed, one district in San Francisco could’ve continued to elect a Republican until as late as 1980, the Bill Mailliard-Dan Burton seat).
Add in Pete Wilson, and in one shot, he gave up the last final GOP charge for majority status in 1996/98, and we’ve been a shadow of that since.