also relied in part on Romer. Notably, O'Connor's opinion did not claim to apply a higher level of scrutiny than mere rational basis, and the Court has not extended suspect-class status to sexual orientation. While the courts have applied rational-basis scrutiny to classifications based on sexual orientation, it has been argued that discrimination based on sex should be interpreted to include discrimination based on sexual orientation, in which case intermediate scrutiny could apply to gay rights cases. Other scholars disagree, arguing that "homophobia" is distinct from sexism, in a sociological sense, and so treating it as such would be an unacceptable judicial shortcut. In 2013, the Court struck down part of the federal Defense of Marriage Act, in United States v. Windsor. No state statute was in question, and therefore the Equal Protection Clause did not apply. The Court did employ similar principles, however, in combination with federalism principles. The Court did not purport to use any level of scrutiny more demanding than rational basis review, according to law professor Erwin Chemerinsky. The four dissenting justices argued that the authors of the statute were rational. In 2015, the Supreme Court held in Obergefell v. Hodges that the fundamental right to marry is guaranteed to same-sex couples by both the Due Process Clause and the Equal Protection Clause of the Fourteenth Amendment to the United States Constitution and required all states to issue marriage licenses to same-sex couples and to recognize same-sex marriages validly performed in other jurisdictions. Affirmative action Affirmative action is the consideration of race, gender, or other factors, to benefit an underrepresented group or to address past injustices done to that group. Individuals who belong to the group are preferred over those who do not belong to the group, for example in educational admissions, hiring, promotions, awarding of contracts, and the like. Such action may be used as a "tie-breaker" if all other factors are inconclusive, or may be achieved through quotas, which allot a certain number of benefits to each group. During Reconstruction, Congress enacted race-conscious programs primarily to assist newly freed slaves who had personally been denied many advantages earlier in their lives. Such legislation was enacted by many of the same people who framed the Equal Protection Clause, though that clause did not apply to such federal legislation, and instead only applied to state legislation. Likewise, the Equal Protection Clause does not apply to private