SAN FRANCISCO (BCN) ― A total of 15 California cities and counties have now joined forces to urge the state Supreme Court to strike down a voter-approved ban on same-sex marriage.

The new number of local governments participating in the case was announced in a revised lawsuit submitted to the high court in San Francisco on Wednesday by San Francisco City Attorney Dennis Herrera.

The lawsuit challenging the ban, enacted by California voters as Proposition 8 on Nov. 4, was originally filed on Nov. 5 by the cities of San Francisco and Los Angeles and Santa Clara County.

Other cities and counties have gradually joined since then.

They are the counties of Alameda, Los Angeles, Marin, San Mateo
and Santa Cruz and the cities of Fremont, Laguna Beach, Oakland, San Diego, Santa Cruz, Santa Monica and Sebastopol.

Herrera said the cities and counties represent more than 17 million Californians.

Herrera said, “I am hopeful that the Supreme Court will recognize what a profoundly threatening precedent Proposition 8 poses to all our constitutional rights, and will strike it down.”

The local government challenge is one of three accepted by the court for review on Nov. 19. The panel’s decision is expected sometime next spring or summer, after briefing and a hearing are completed.

The other two suits were filed by seven same-sex couples and a marriage equality group. All three lawsuits contend that Proposition 8, which was passed as a constitutional amendment, was so sweeping that it is a constitutional revision rather than an amendment.

A revision would require approval of two-thirds of the Legislature as well as a majority of voters in order to be enacted.

Responses in defense of Proposition 8 by state Attorney General Jerry Brown and the sponsors of the measure are due by Dec. 19.

Additional filings, including friend-of-the-court briefs by other groups, are due in January and the court is expected to hear arguments in March. Its written decision will be due 90 days after the hearing.

Proposition 8 amended the state constitution to provide that “only marriage between a man and a woman is valid or recognized in California.”

It overturns a decision in which the court ruled by a 4-3 vote in May that the constitution’s guarantee of equal protection provides a right to gay and lesbian marriage.

The revised local-government lawsuit also seeks permission to add as plaintiffs seven same-sex couples who were married before Nov. 4 and want to argue that Proposition 8 did not retroactively invalidate their marriages.