> Unless I'm reading this[1] wrong, the California State Assembly has been a Democrat supermajority since 2011, and the Senate has been since 2013.
The relevant threshold is 27 (2/3 of 40 is 26.6...) seats in the Senate, 54 (2/3 of 80 is 53.3...) in the Assembly.
So in 2011 neither house has a supermajority (and, prior to a State Constitutional Amendment in 2010, a supermajority was required to pass a budget with or without tax changes), in 2013 Dems had supermajorities in both Houses which they lost for the 2015 session in both Houses, regained in 2017 by the 2016 election in both Houses, lost in the Senate by a recall in mid 2018, and regained by the 2018 elections for the 2019 session.
> Moreover, Democrats have only been one or two votes short of a supermajority in both houses since 1999.
No, up to 2 in the Senate and 6 on the Assembly short; and up until 2010 that meant Republicans, while, they couldn't pass anything on their own obviously, had a veto on the annual budget which thhey regularly held hostage to extract other concessions.
> So, I still think my statement is fair, that the GOP has no effective power in California, and that has been the case for two decades.
It's not; they've had a veto on tax policy changes that aren't pure cuts intermittently, on at least one house (which is all it takes) over the last decade, and a veto over the budget consistently for the prior decade.
Oh, and as well as a legislative veto on the budget they also held the Governor's office for much of that prior decade (the full years of 2004-2010), which gave them more power (especially because, unlike the President in the federal system, the Governor has a line item veto on the California budget.)
So, no, they haven't been without power in California for two decades (or even the original claim of one, but its much more ridiculous to now claim two.)