The bill must still pass the Assembly, where it was narrowly defeated in June, before it reaches Gov. Arnold Schwarzenegger, who opposes same-sex marriage but supports domestic partnerships.

The Senate vote is expected to quickly reignite one of the most emotional and politically contentious issues in contemporary politics. Already, two initiatives are being circulated to put a constitutional ban on gay marriage before voters next year.

But whether Thursday's dramatic action goes down as the first in a wave of growing legislative support for same-sex marriage or as a high-water mark for gay rights now rests with a handful of moderates who could risk political suicide by supporting it. Almost all of the 10 Assembly Democrats who abstained or voted against gay marriage in June face tough elections next year in swing districts or represent heavily Latino or Catholic constituencies that generally oppose it.
