As the most senior Supreme Court justice inclined to support marriage equality, Anthony Kennedy enjoyed the right of first refusal to author the Court’s opinion in Obergefell v. Hodges; and as the only conservative on the Court willing to take the constitutional leap, the fate of marriage equality apparently hung in a precarious balance.

Under a less fragile arrangement, the ruling probably would have looked much different. Chief Justice John Roberts wrote the Court’s 6-3 opinion in King v. Burwell—and it shows—but it also reads like a consensus document that was circulated among its five co-signers, each of whom enjoyed fair input.

Kennedy’s Obergefell ruling is nothing like that. He succeeded in crafting a few poignant passages about the struggle for and righteousness of equality. And, of course, his ultimate holding was the correct one. But the price of admission for the Court’s four liberals was to join a muddled, unconvincing opinion.

Outside of academic specialties, historic Supreme Court decisions aren’t generally taught as logical treatises, but as watershed moments, which is great news for Kennedy because his opinion in Obergefell is, logically speaking, kind of a disaster. On those rhetorical merits, Chief Justice John Roberts completely outmatched him. Which is too bad, because a decision as solemn and momentous as the Court made Friday ought to hold up well not just as a historically impressive step, but a convincing one as well. A win is a win, but in this particular victory lies a reminder that liberals should make getting a fifth liberal justice on the Court an overriding priority.

As both a moral and legal issue, arguing for marriage equality (or, equivalently, for government neutrality on marriage) should be fairly easy: States and the federal government recognize a contractual situation called marriage, and through that recognition flows vague public sanction, manifest through real, tangible, legal preferences. The best constitutional argument for same-sex marriage is that the state can’t deny those benefits—conceptual or concrete—to gays and lesbians on the basis of their sexual orientation, or only bequeath them to gays and lesbians who are willing to enter into marriage contracts with people of the opposite sex whom they don’t truly love.