Solicitor General Donald B. Verrilli filed briefs in support of opponents of Prop 8. The government argued in court that laws that ban gay marriage should be subject to heightened scrutiny from the courts. Verrilli said that Prop 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, is a violation of equal protection.
Before the justices got to the merits of the case, they had to determine whether the proponents of Prop 8 had the legal right to be in court in the first place. Cooper argues that the California Supreme Court gave the sponsors the states' authority to defend the law and that the U.S. Supreme Court should respect that. Olson said Protectmarriage.com does not have the necessary injury that would satisfy standing.