Next week, the Supreme Court will assemble for the term’s opening conference. With a half dozen same-sex marriage cases already waiting on their desks, the justices may decide to step in and finally put the issue to rest. If the Court chooses to hear the cases, there is little suspense—though still excitement—about how the Court will ultimately rule: Justice Anthony Kennedy will vote with the liberals, and recognition of same-sex marriage will become the law of the land. But another question remains. When the Court rules, will it do so modestly, simply demanding that marriage everywhere expand to include gays? Or will the justices do something bolder and better for American family life: Explain that marriage doesn’t need to be expanded for same-sex couples, because it has always included them.

Since the Court struck down DOMA last year, all three appellate courts that have ruled have reached similar conclusions: The U.S. Constitution compels states to recognize same-sex marriages. But the current unanimity among the courts of appeals is deceptive. The courts don’t simply render judgments; they also write opinions. And in their reasoning, the circuit courts have spoken in two very different voices: On one account, gay Americans are a persecuted group against whom states are discriminating. On the other, marriage is a fundamental right that that the states are restricting unjustly.

Taking the former route is the 7th Circuit Court of Appeals, which published its ruling just two weeks ago. In an opinion from the iconoclastic Judge Richard Posner, the court deliberately brushed aside questions about the importance of marriage or its status as “a fundamental right.” Instead, Posner argued methodically that state marriage law subjects gays to constitutionally prohibited discrimination: Gays are an “identifiable group of persons” who have been subjected to “unequal treatment” by their state governments. And after patient (and at times hilarious) investigation, Posner concludes that the unequal treatment simply cannot be rationalized by an “offsetting benefit to society.” Philosophical posturing about the definition of marriage is beside the point. Discrimination is the key issue, and must be justified in some vaguely convincing manner. For Posner, marriage is an artificial institution created by men and law. Once created, it must be expressed equally, and gays and straights must have equal access.

This approach contrasts sharply with that of the 10th Circuit, which was the first appellate court to rule on the issue this past June. Perhaps the most striking element of its decision is that it barely mentions homosexuality at all. Previous gay rights cases like U.S. v. Windsor and Lawrence v. Texas make occasional appearances in the decision, but concerns about discrimination lie outside of the majority’s main argument. Liberty and personal freedom are the issue; identity, orientation, and homosexuality are close to irrelevant. In the words of the court, “those who wish to marry a person of the same sex are entitled to exercise the same fundamental right as is recognized for persons who wish to marry a person of the opposite sex.” That’s right: “those who wish to marry a person of the same sex.” In a brilliant bit of judicial jujitsu, the 10th Circuit makes gay identity marginal to the gay marriage debate.

Instead, the 10th Circuit Court of Appeals embraced a deeply rooted “right to marry” as the starting point for its evisceration of Utah’s ban on same sex marriage. Confronted with a gay Salt Lake City couple denied a marriage license, the court explained “there can be little doubt that the right to marry is a fundamental liberty.” And in flowery selections from previous cases, the court reflected on marriage’s significance: A right to marry is “older than the Bill of Rights” and “implicit in the concept of ordered liberty, such that neither liberty nor justice would exist if [it] were sacrificed.” The central question, then, became the scope of this fundamental right—a right that is older, deeper, and independent of our political processes. If this right includes a right to marry a member of the same sex, then the state laws must fall.

By framing the question this way, the 10th Circuit demonstrated that it wasn’t interested in subjecting a man-made institution (marriage) to constitutional demands of non-discrimination. Other courts asked: Have states created an institution that violates equality? But the judges of the 10th Circuit assumed “marriage” as a preexisting concept already protected by the Constitution, and asked a deeper, and far more radical, question: Do state laws conform to this prior, almost metaphysical, concept of marriage? Like other courts, the 10th Circuit entertained the claim that procreation might somehow be essential to marriage, and that the right to marry might actually be “a right to marry a member of the opposite sex.” And like those other courts, the 10th Circuit found too many contrary examples in precedent and legal structure to accept that proposition. But when looking to precedent and principle, the 10th Circuit was engaged in a fundamentally different project than the other courts. While these other judges acted as investigators seeking inconsistency and animus, the judges of the 10th Circuit were explorers uncovering the shape and contours of an idea.

At first glance, the approach of the 10th Circuit seems more radical, but it is also deeply conservative—in all the right ways. On the one hand, it is welcoming, not only inviting gay couples into humanity’s oldest social institution, but telling them that they have always belonged there. At the same time, it should also be easier for opponents of same-sex marriage to stomach: I would rather be told that the Court disagrees with my metaphysics than be labeled a bigot. And most importantly, it represents a public and explicit affirmation of the centrality of marriage more generally. Marriage, the Court could reaffirm, is older than politics, fundamental to civilization, and implicit in constitutional notions of liberty. Its definition is a reality to be understood, not a legal fiction created in time and restricted at will. It is, to borrow a term from same-sex marriage opponents, sacred. And the cavalier way in which marriage is increasingly approached (or ignored) is an embarrassment. A ruling in the footsteps of the 10th Circuit would be both a more profound embrace of gay couples, and a more universal expression of social values.

Which route will Justice Kennedy eventually take? There is ample precedent for either in his Windsor decision. But his sometimes mocked philosophizing in Planned Parenthood v. Casey (“At the heart of liberty is the right to define one's own concept of existence, of meaning, of the universe, and of the mystery of human life.”) indicates an openness to the approach of the 10th Circuit. This is a good thing.

Twenty five years ago, Andrew Sullivan published his now famous “Here Comes the Groom: A (Conservative) Case for Gay Marriage.”  At the time, he argued that gay marriage would be good for gays and good for society. But even Sullivan didn’t suggest that a court decision on the issue might represent one of the great statements of marriage’s metaphysical reality and importance to civilization. But that is what the 10th Circuit has done. The Supreme Court should follow suit.