You can read the entire 138 page ruling on Scribd. Ultimately, the judge concluded the following:
Proposition 8 fails to advance any rational basis in singling out gay men and lesbians for denial of a marriage license. Indeed, the evidence shows Proposition 8 does nothing more than enshrine in the California Constitution the notion that opposite-sex couples are superior to same-sex couples. Because California has no interest in discriminating against gay men and lesbians, and because Proposition 8 prevents California from fulfilling its constitutional obligation to provide marriages on an equal basis, the court concludes that Proposition 8 is unconstitutional.The constitutional obligations refer to the Due Process and Equal Protection Clauses of the Fourteenth Amendment which prohibit state and local governments from depriving people of life, liberty, or property without the process and proceedings of the courts of justice. For example, taking away somebody's right to marry.
Coincidentally, the Fourteenth Amendment to the U.S. Constitution also has that Citizenship Clause we've been hearing so much about lately. Some congressman (Lindsey Graham, Chuck Grassley, I'm looking at you) are hyperventilating over "anchor babies" and are radically suggesting that birthright citizenship is a mistake and that the Amendment should be transformed or even repealed. This would of course create a permanent underclass of immigrant workers... exactly what the Fourteenth was designed to prevent!
At one point in history, Republicans viewed passage of this Amendment as an accomplishment. However, 144 years later, they're having second thoughts.
But hey, if they can repeal it now, they can re-institute slavery and block same-sex marriage all in one move! And though I don't like conspiracy theories, I wouldn't doubt that these are the exact intentions of some members of the Republican party.
Anyway, if you want a same-sex marriage in California, you better do it before they overturn the overturn.