In a "friend of the court" brief filed at the deadline, Solicitor General Don Verrilli argues:
Proposition 8’s denial of marriage to same-sex couples, particularly where California at the same time grants same-sex partners all the substantive rights of marriage, violates equal protection. The Fourteenth Amendment’s guarantee of equal protection embodies a defining constitutional ideal that “all persons similarly situated should be treated alike.
The object of California’s establishment of the legal relationship of domestic partnership is to grant committed same-sex couples rights equivalent to those accorded a married couple. But Proposition 8, by depriving same-sex couples of the right to marry, denies them the “dignity, respect, and stature” accorded similarly situated opposite-sex couples under state law, Strauss, 207 P.3d at 72, and does not substantially further any important governmental interest. It thereby denies them equal protection under the law.
Under that argument, Verrilli said, same-sex marriage in seven other states with broad domestic partnership rights already on the books would also immediately become legal.
The so-called "eight state solution" would cover: California, Delaware, Hawaii, Illinois, Nevada, New Jersey, Oregon and Rhode Island.
That logic could, in theory, challenge bans on same-sex marriage in states that have constitutional bans.
Proposition 8 was originally passed by California voters in November 2008 to deny same-sex couples the right to marry after the California courts had ruled gay marriage legal. Thus, thousands of California gay couples hold legal marriages in the state, while for others marriage is inaccessible, thus providing the argument made by the Ninth Circuit Court in overturning the measure.
Nine states and the District of Columbia already allow same-sex marriage, five by state legislature (Maryland, New Hampshire, New York, Vermont, Washington), three by court rulings (Connecticut, Iowa, Massachusetts) and one by voter-approved ballot (Maine).