Notice how I phrased that subject line. I'm going to quote this post by
maiac (found via a comment on this post by
trektone), which explains it much better than I can:
Specifically, the Court ruled that it's unconstitutional to make a
distinction between opposite-sex couples and same-sex couples such that
only opposite-sex couples are permitted the full recognition of their
committed relationship that the term marriage bestows.
Here's a longer quote (emphasis mine) from full
decision [PDF]:
...under this state's Constitution, the constitutionally based
right to marry properly must be understood to encompass the core set of
basic substantive legal rights and attributes traditionally associated
with marriage that are so integral to an individual's liberty and personal
autonomy that they may not be eliminated or abrogated by the Legislature
or by the electorate through the statutory initiative process.
These core substantive rights include, most fundamentally, the opportunity
of an individual to establish -- with the person with whom the individual
has chosen to share his or her life -- and officially recognized and
protected family possessing mutual rights and responsibilities and
entitled to the same respect and dignity accorded a union traditionally
designated as marriage. As past cases establish, the substantive right of
two adults who share a loving relationship to join together an officially
recognized family of their own -- and, if the couple chooses, to raise
children within that family -- constitutes a vitally important attribute
of the fundamental interest in liberty and personal autonomy that the
California Constitution secures to all persons for the benefit of both the
individual and society.
Furthermore, in contrast to earlier times, our state now recognizes that
an individual's capacity to establish a loving and long-term committed
relationship with another person and responsibly to care for and raise
children does not depend upon the individual's sexual orientation, and,
more generally, that an individual's sexual orientation -- like a person's
race or gender -- does not constitute a legitimate basis upon which to
deny or withhold legal rights.
[...]
One of the core elements of the right to establish an officially
recognized family that is embodied in the California constitutional right
to marry is a couple's right to have their family relationship accorded
dignity and respect equal to that accorded other officially recognized
families, and assigning a different designation for the family
relationship of same-sex couples while reserving the historic designation
of "marriage" exclusively for opposite-sex couples poses at least a
serious risk of denying the family relationship of same-sex couples such
equal dignity and respect.
[...]
...retaining the designation of marriage exclusively for opposite-sex
couples and providing only a separate and distinct designation for
same-sex couples may well have the effect of perpetuating a more general
premise -- now emphatically rejected by this state -- that gay individuals
and same-sex couples are in some respects "second-class citizens" who may,
under the law, be treated differently from, and less favorably than,
heterosexual individuals or opposite-sex couples.... Accordingly, we
conclude that to the extent the current California statutory provisions
limit marriage to opposite-sex couples, these statutes are
unconstitutional.
It's worth noting that only one of the court's seven members is a
Democratic appointee. That, plus the wording of the decision, makes it
likely that it will stand up even after the inevitable initiative
ammendment attempting to narrow the definition of "marriage" passes.
What it comes down to is that "marriage" as defined by the state of
California is a civil contract between consenting adults (only two, at the
moment, but one can hope for that, too, to change eventually) that
formally recognizes a family relationship between them. Period.
It has nothing to do with religion. If a religion expects its followers
to believe in a narrower definition of the word, they can, just as they
can believe in a narrower definition of the word "priest", or that the
entire universe was created in its present form in seven days, or that the
sun revolves around an unmoving Earth. As Galileo once said,
"nevertheless, it moves."
Just don't try to tell my daughters who they can marry, or who has the
power to marry them. In California the answer to "who can they marry" is
now "anyone", just like the answer to "who has the power" has been for
several decades.