Did Proposition 187 irreparably damage the GOP in California? (No: just a myth spread by illegal immigration supporters)

One of the oft-repeated claims by those who support illegal/massive immigration is that Proposition 187 irreparably damaged the Republican party in California. Those spreading that claim include many Democratic leaders but also Republicans such as frequent quote source Allan Hoffenblum.

Now, see this:

There is little evidence that the California ballot initiatives had any effect on the GOP's performance with any racial or ethnic group, and hence little to suggest that the Arizona GOP will suffer the same fate.

The "Prop 187 killed the California GOP" narrative is first based upon a misconceived view of the Republican Party's historic strength in California. While the Republican Party nominated Californians for President five times between 1960 and 1988, which is certainly a testament to the GOP's strength in the Golden State, the party was in decline well before the mid-1990s. [see chart at link]

...The Democrats have held a large, steady registration advantage in the state for the better part of a century. You'll note that the Democrats' registration advantage doesn't expand post-1994 (as we would expect if the mid-decade propositions had a massive negative effect on the GOP). In fact, the ratio of registered Republicans to registered Democrats in 2000 is within two-tenths of a point of where it was in 1994.

This advantage has long manifested in statewide races. While the GOP frequently carried California at the Presidential level in the latter half of the Twentieth Century, the Republicans have not won an outright majority of the State Senate since 1954, and have only won the State Assembly twice since then. As for statewide races, (Kos) is correct that the GOP has not performed particularly well since 1994, but it is also true that, since 1954, the Republicans rarely won more than one of the four down ballot spots, save for the GOP landslide years of 1966 and 1994.

If you're not sure about the answer to the titular question, see the charts and more specific data at the link.