California’s Proposition 8 allows same sex couples to join through civil unions, which grant the legal benefits afforded to married couples but denies them the official label of “marriage.” The lower court eschewed the question of whether Proposition 8 burdens any fundamental right by concluding there is not even a rational basis (the minimum standard for the constitutionality of any law) for this law, as its sole effect is to deny same sex couples the designation of marriage.

We appreciate the lower court’s caution not to extend our fundamentalrights jurisprudence beyond precedent. However, we are positioned to elaborate fundamental constitutional rights in ways that the lower court could not. Today we conclude that Proposition 8 burdens a fundamental right. To state that this law does not offend the fundamental liberty and dignity protected by the Due Process Clause misunderstands the nature and extent of “the liberty at stake.” It is apparent that denying people in same sex relationships the option of marriage, when it is a course of action available to all other individuals, impairs freedom and dignity inherent in the substantive liberty guarantees of the Constitution. The Due Process Clause protects personal liberty because it stems from the inherent worth–the dignity–that arises from each person’s “capacity for self-conscious individuation.” Because “the ability independently to define one’s identity .. . is central to any concept of liberty,” 7 dignified liberty requires the state to respect personal, identity-defining choices. Because Proposition 8 disrespects such choices, it must be subject to strict scrutiny; the law may only stand if necessary and narrowly tailored to achieve a compelling state interest.

In evaluating the state’s compelling interest in prohibiting same-sex marriage, we understand that modifying marriage creates the potential for change in traditionally defined social roles and responsibilities, presenting the possibility of unknown consequences for social stability and welfare. But there has not yet been any evidence demonstrating harmful consequences of modifying marriage. In a democracy that embraces individual freedom as well as the progress that comes from experimentation and innovation, we cannot burden constitutional liberty interests based on the mere potential for unknown consequences. We recognize that this debate involves more than the question of whether same sex marriage has been shown to pose a risk to social welfare; it also represents competing cultural values. Thus, we cannot expect to reach a solution that satisfies both sides solely by determining whether evidence shows that same sex marriage threatens welfare and social stability. We will consider the cultural values underlying both sides of this debate in our decision, so that the law may express all of the neutral public values perceived to be at stake, rather than expressing one cultural group’s dominance over the other. Opponents of same sex marriage cherish legitimate cultural values such as responsibility, adherence to traditional order, and stability, which they recognize as critical to public welfare. Upon examining the testimony of experts on marriage and those seeking same-sex marriages, it is apparent that same sex couples wish to conform to, rather than reform, the values that opponents of same sex marriage cherish. Proposition 8 fails strict scrutiny because none of the evidence shows that same sex marriage threatens welfare or stability of families. Rather, same sex marriage appears to advance the respectable values of responsibility, tradition, and stability that its opponents believe integral to societal welfare.