While California’s debate over gay marriage will begin in earnest next month with proposed legislation at the Capitol, the state’s political watchdog has already weighed in.

The state Fair Political Practices Commission (FPPC) ruled this morning that as far as campaign finance laws are concerned, registered domestic partners are, in fact, “spouses” when it comes to the state’s Political Reform Act.

In summary, the issue arose after a candidate for the Solana Beach City Council (San Diego County) wanted to know the impact of the soon-to-be-enforced state law expanding the rights and obligations of domestic partners. Candidates and campaigns often must disclose exactly who’s related to whom when it comes to where money goes, and where it came from… thus the need to know whether a domestic partner was, in these cases, also a “spouse.”

This morning, the FPPC voted 4-1 to include domestic partners as “spouses”. This, of course, does nothing to answer the question in the larger battle over gay marriage… but expect much to be made of it, by both sides, in the coming days.