Generally, he wouldn't have the power to officiate a marriage in California. See California Family Code section 400 and so on. Basically, only religious clergy and state officials can do that. That's the culture and law that applies in Berkeley, California.

There seems to be an exception under which someone can become a temporary "deputy commissioner of marriages" for the purpose of one ceremony. If you don't believe in religion, and (like me) you fear that the government has its own PHYGish tendencies, this doesn't seem like a bad alternative.