Marriage equality activists across America have been celebrating yesterday’s landmark decision by the California Supreme Court that the state can no longer exclude same-sex couples from civil marriage.

The court ruled that lesbian and gay couples are entitled to the same fundamental right to marry as heterosexual couples as protected by the California constitution.

The decision explicitly strikes down Proposition 22, a voter-passed initiative in 2000 that sought to limit marriage to between a man and woman.

Under California rules of procedure, the decision can not go into effect for at least 30 days.

While it was a  4-3 decision, the language used by the court in relation to the nature of gay and lesbian relationships sends a clear message that the state should treat all citizens equally regardless of their sexual orientation.

“In contrast to earlier times, our state now recognises that an individual’s capacity to establish a loving and long-term committed relationship with another person and responsibly to care for and raise children does not depend upon the individual’s sexual orientation,” the court ruled.

“More generally, an individual’s sexual orientation, like a person’s race or gender, does not constitute a legitimate basis upon which to deny or withhold legal rights.

“We therefore conclude that in view of the substance and significance of the fundamental constitutional right to form a family relationship, the California Constitution properly must be interpreted to guarantee this basic civil right to all Californians, whether gay or heterosexual, and to same-sex couples as well as to opposite-sex couples.”

Congresswoman Tammy Baldwin, the only out lesbian in Congress, captured the mood:

“Like many Americans, I’m elated by today’s California State Supreme Court ruling that laws excluding gay and lesbian couples from the right to marry were unconstitutional,” she said.

“There will be more legal and political challenges ahead as we continue our march toward full equality for all Americans.  But today is a day to savour the moment and recall what Dr King often preached: “The arc of the moral universe is long, but it bends toward justice.”"

The California Supreme Court agreed to hear the case in 2006 after the California Court of Appeal reversed a decision by San Francisco Superior Court Judge Richard A. Kramer that barring same-sex couples from marriage unconstitutionally discriminates on the basis of sex and violates the fundamental right to marry.

California has the highest number of same-sex couples of any US state.

Fourteen of them were represented by the National Centre for Lesbian Rights, Lambda Legal, the American Civil Liberties Union, Heller Ehrman LLP, and the Law Office of David C. Codell.

The City and County of San Francisco filed its own challenge to the marriage laws, represented by the office of City Attorney Dennis Herrera. The cases, along with four others, were consolidated into one appeal.

“We have waited more than 50 years for the opportunity to marry,” said Phyllis Lyon, on behalf of herself and Del Martin, who were plaintiffs in the case.

Lyon, 83, and Martin, 87, have been together 56 years. “We are thrilled that this day has finally come.”

The court based its decision on what it termed: “the fundamental nature of the substantive rights embodied in the right to marry, and their central importance to an individual’s opportunity to live a happy, meaningful, and satisfying life as a full member of society, the California Constitution properly must be interpreted to guarantee this basic civil right to all individuals and couples, without regard to their sexual orientation.”

“We’re tremendously gratified that the Court today has fulfilled its traditional duty,” said Jennifer Pizer, Senior Counsel for Lambda Legal.

“Like the 1948 decision recognising the right of interracial couples to marry, this ruling keeps a promise that every Californian should hold dear: the California Constitution embraces everyone equally.

“Each of us depends on the Supreme Court to enforce our basic rights to be free and equal under law, no more and no less than our neighbours and friends.

“Enforcement was essential for mixed-race families in the 1940s and for women in the 1970s, and it’s essential for gay men and lesbians now. California’s Constitution safeguards all of us.”

“All Californians should be incredibly proud of our state for leading the nation in ending the unnecessary pain that is caused when lesbian and gay couples are barred from the legal protections and dignity that come through marriage,” said Maya Harris, Executive Director of the ACLU of Northern California. “Today marks a defining moment in our state’s already rich history of establishing fairness for all.”

Currently, lesbian and gay couples may legally marry in Massachusetts, Canada, Spain, the Netherlands, Belgium, and South Africa.

In 2007, an Iowa trial court held that Iowa’s marriage ban violates the Iowa Constitution. That case is now before the Iowa Supreme Court.

A lawsuit challenging the exclusion of same-sex couples from marriage in Connecticut is also pending before the Connecticut Supreme Court.

Right-wing organisations are attempting to amend the California Constitution to openly discriminate against lesbian and gay couples, Lambda Legal said.

“Groups funded by out-of-state organisations have submitted signatures to place an initiative on the November ballot that would ask voters to alter the constitution by denying gay and lesbian couples the freedom to marry, which the court upheld today,” is said in a statement.

The California secretary of state has not yet determined if the discriminatory initiative has qualified for the November ballot.

The state’s Governor, Arnold Schwarzenegger has called any such initiative a waste of time and pledged he would fight against it.

To read the court’s decision, click here.