San Francisco -- California's highest court today ruled that the state's ban on marriage for same-sex couples is unconstitutional and that state authorities must take steps to grant full equality in marriage to all couples.
The court described the right to marry [p 6] as one of the "core substantive rights" for all citizens of California.
[T]he substantive right of two adults who share a loving relationship to join together to establish an officially recognized family of their own -- and, if the couple chooses, to raise children within that family -- constitutes a vitally important attribute of the fundamental interest in liberty and personal autonomy that the California Constitution secures to all persons for the benefit of both the individual and society.
One of the justices writes [p 126], "Absent a compelling justification, our state government may not deny a right as fundamental as marriage to any segment of society."
In its majority opinion, the court voids a state law that limits marriage to heterosexual couples [p 120]:
[W]e determine that the language of section 300 limiting the designation of marriage to a union “between a man and a woman” is unconstitutional and must be stricken from the statute, and that the remaining statutory language must be understood as making the designation of marriage available both to opposite-sex and same-sex couples. In addition, because the limitation of marriage to opposite-sex couples imposed by section 308.5 can have no constitutionally permissible effect in light of the constitutional conclusions set forth in this opinion, that provision cannot stand.
The ruling calls for a "writ" that would direct "the appropriate state officials to take all actions necessary to effectuate our ruling in this case so as to ensure that county clerks and other local officials throughout the
state, in performing their duty to enforce the marriage statutes in their jurisdictions, apply those provisions in a manner consistent with the decision of this court."
The majority decision was written by Chief Justice Ronald M. George with concurrence by Associate Justices Joyce L. Kennard, Kathryn Mickle Werdegar, and Carlos R. Moreno.
With the ruling, California becomes the second state after Massachusetts where gays and lesbians can legally wed. The decision becomes final in 30 days. Unlike Massachusetts, California does not have a statute limiting marriage in the state to residents, so it's expected to become possible for couples from other states to be married in California.
Kennard writes in her own concurring opinion emphasizes that the court's ruling is one about basic rights for all California citizens:
In holding today that the right to marry guaranteed by the state Constitution may not be withheld from anyone on the ground of sexual orientation, this court discharges its gravest and most important responsibility under our constitutional form of government. There is a reason why the words “Equal Justice Under Law” are inscribed above the entrance to the courthouse of the United States Supreme Court. Both the federal and the state Constitutions guarantee to all the “equal protection of the laws”, and it is the particular responsibility of the judiciary to enforce those guarantees.
The eagerly anticipated Supreme Court ruling was released at 10am (PDT) today on the court's website. (Interest in the decision was so high that the site was occasionally unavailable.)
The court considered this issue: "Does California’s statutory ban on marriage between two persons of the same sex violate the California Constitution by denying equal protection of the laws on the basis of sexual orientation or sex, by infringing on the fundamental right to marry, or by denying the right to privacy and freedom of expression?"
Kennard emphasized in her concurring opinion that equal rights is something that must often be enforced by courts even when the issue is unpopular:
The architects of our federal and state Constitutions understood that widespread and deeply rooted prejudices may lead majoritarian institutions to deny fundamental freedoms to unpopular minority groups, and that the most effective remedy for this form of oppression is an independent judiciary charged with the solemn responsibility to interpret and enforce the constitutional provisions guaranteeing fundamental freedoms and equal protection.

Supporters of marriage equality have scheduled a "celebration of love and family" at the San Francisco LGBT Center, 1800 Market St., at 5 pm today, with similar observances planned in Los Angeles, Sacramento, San Luis Obispo and Palm Springs, San Francisco Chronicle reports.
"Express your joy - or frustration - with dignity and resoluteness," the advocacy group Equality California advised participants in an e-mail message.
The court heard oral arguments for the case in an extraordinary three hour session on March 4.
Today's ruling responds to a series of cases that challenge California's ban on same-sex marriage and a 2000 voter-approved ballot initiative that defines marriage as a union between a man and woman.
The challenges stem from a February 2004 decision by San Francisco Mayor Gavin Newsom to let same-sex get marriage licenses from City Hall.
After the city of San Francisco had granted about 4,000 licenses in four weeks the practice was halted by the Supreme Court responding to a lawsuit by the state's attorney general. The court later ruled the city had no authority to issue the licenses and that they were invalid.
But the high court said it was willing to allow separate proceedings to test the constitutionality of the state marriage laws.
Eventually, six lawsuits were filed -- four by the city of San Francisco and the three sets of same-sex couples and two by the groups opposing same-sex marriage. The state attorney general's office and governor became parties to defend the state laws.
The city of San Francisco and three sets of a total of 19 same-sex couples argued in March that a ban on same-sex marriage is unconstitutional.
On the other side, the state marriage laws was defended by lawyers representing California Attorney General Jerry Brown, Gov. Arnold Schwarzenegger, the Campaign for California Families and the Proposition 22 Legal Defense and Education Fund.
Over time, the California legislature has granted to gay and lesbian couples virtually all the rights of marriage through the state's domestic partnership program. Domestic partners may make medical decisions for each other, receive employee benefits through a partner, hold parental rights with a partner's child. Most recently, in 2006, the legislature gave registered domestic partners the right to file joint state tax returns.
But the term "marriage" has been reserved, up to now, only for heterosexual couples.
Schwarzenegger has twice vetoed bills passed by the legislature that would have authorized "marriage" for same-sex couples. In rejecting the measures, he said he thinks the question should be up to voters or the courts, not lawmakers.
The Supreme Court decision concludes that those "separate, but equal" rights are not enough to meet the state constitution's guarantee of equal protection. In a press release accompanying the decision, the court explained:
Although the opinion acknowledges that the recent comprehensive domestic partnership legislation enacted in California affords same-sex couples most of the substantive elements embodied in the constitutional right to marry, the opinion concludes that by assigning a different name for the family relationship of same-sex couples while preserving the historic and honored designation of "marriage" only for opposite-sex couples, the California statutes threaten to deny the family relationship of same-sex couples dignity and respect equal to that accorded the family relationship of opposite-sex couples and thereby impinge upon a same-sex couple's right to marry as protected by the California Constitution ...
Right-wing organizations have submitted what they claim to be than 1.1 million signatures for an initiative that would amend the state Constitution to enshrine discrimination in the state's constitution. If at least 694,354 signatures are found to be valid, the measure would go on the November ballot and, if approved by voters, would override any court ruling in favor of same-sex marriage.
Schwarzenegger vowed last month to campaign against the measure if it makes it onto the ballot. He repeated his opposition today to the proposed anti-gay amendment.
[This story was modified several times through the day to add more information. It's a complex 172 page decision with several concurring and dissenting opinions.]