SAN FRANCISCO—In a major victory for same-sex couples Jan. 3, the California Supreme Court denied a petition by county assessors seeking review of a California Court of Appeal decision affirming the validity of basic property tax protections for domestic partners. The court’s decision means that the validity of these protections is secure. No further appeals are possible.

On Oct. 3, the California Court of Appeal unanimously affirmed the validity of a California Board of Equalization rule that protects domestic partners from increased property taxes when one of the partners dies and the other inherits the couple’s home. California law has long provided this protection for surviving heterosexual spouses.

The case began in March 2005 when Sutter and Orange Counties challenged the rule in state court. Represented by the National Center for Lesbian Rights, Lambda Legal, and the law firm of Munger, Tolles and Olson LLP, Equality California and three same-sex couples intervened in the litigation to defend the rule. Orange County later left the litigation, but Tehama and Madera Counties joined it. Last week’s decision affirmed the rule.