Actually, Prop 8 amended to the California constitution to expressly say that marriage is the union of a man and a woman.
California law already said this when the proposition was being prepared for the ballot. It was designed to head off a court from creating a right to neutered marriage licensing. But before the vote, the state's Supreme Court ordered the neutering of marriage licensing.
There are two issues here.
1. Should state marriage licensing be changed to neuter marriage?
2. Who should decide?
Proposition 8 restored the will of THE PEOPLE of California.
http://walrus.blogtownhall.com/2008/11/02/the_case_for_prop _8.thtml