From the chair of California's Libertarian Party:
People who truly cherish freedom see today's Supreme Court decision as a victory for liberty and common sense. There's no reason why consenting adults should not be allowed to marry so long as their arrangement doesn't interfere with any other individual's ability to live their life in any way they want to.
Many supporters see the decision as a repudiation of bigotry and narrow-mindedness. But Libertarians also see it as a step towards a revision of the larger public policy issue surrounding marriage. Californians should start asking their elected officials why government is involved in granting marriage licenses at all.
And here's Libertarian presidential hopeful Bob Barr (via Marc Ambinder):
Regardless of whether one supports or opposes same sex marriage, the decision to recognize such unions or not ought to be a power each state exercises on its own, rather than imposition of a one-size-fits-all mandate by the federal government (as would be required by a Federal Marriage Amendment which has been previously proposed and considered by the Congress). The decision today by the Supreme Court of California properly reflects this fundamental principle of federalism on which our nation was founded.