Let the people of California vote on it. Let people file suit and have the Supreme Court strike it down. Then the people of California can decide if it really is important enough to them by electing legislators that will pass that kind of law. If it's all the result of rabble-rousing the idea will die a natural death -- if it really is the will of the people, it will eventually get passed.

BTW, a similar law here in Illinois would have the same effect (except for the Metro Chicago area, most of the state is red) - but since both houses and the governorship are held by Chicagoans, it would never happen here.

The only way that such a change is acceptable is if all states do it, not just the ones that vote democrat. Texas has the same problem. It will always be a red state as long as the electors are decided using the current system.