It's irrelevant what's possible in 2/3 of the US. The California status quo until the court case, which Eich was implicitly trying to restore by supporting prop 8, was civil unions with identical treatment to marriage under state law except the name.
That's not Uganda style death penalty as some are equating it to.
Aside from the ethical issues, civil partnerships only had identical treatment to marriage under Californian state law. They weren't treated as marriages under federal law, or by many other countries and US states that recognised gay marriage. Likewise, Prop 8 meant that the marriages of gay couples from outside the state couldn't be recognised in California.
That's not Uganda style death penalty as some are equating it to.