WASHINGTON — In a historic argument for gay rights, President Barack Obama urged the Supreme Court Thursday to overturn California’s same-sex marriage ban and turn a skeptical eye on similar prohibitions across the country.

The Obama administration’s friend-of-the-court brief marked the first time a U.S. president has urged the high court to expand the right of gays and lesbians to wed. The filing calls on the justices to strike down California’s Proposition 8 ballot measure, although it stops short of the soaring rhetoric on marriage equality Obama expressed in his inaugural address in January.

California is one of eight states that give gay couples all the benefits of marriage through civil unions or domestic partnership, but don’t allow them to wed. The brief argues that in granting same-sex couples those rights, California has already acknowledged that gay relationships bear the same hallmarks as straight ones.

“They establish homes and lives together, support each other financially, share the joys and burdens of raising children, and provide care through illness and comfort at the moment of death,” the administration wrote.

The brief marks the president’s most expansive view of gay marriage and signals that he is moving away from his previous assertion that states should determine their own marriage laws.

Obama, a former constitutional law professor, signed off on the administration’s legal argument last week following lengthy discussions with Attorney General Eric Holder and Solicitor General Donald Verrilli.