Justice Anthony Kennedy today ensured his legacy as the man who, more than any other individual, secured the legal equality of gays and lesbians.

On the 12-year anniversary of his opinion in Lawrence v. Texas, finding state sodomy laws unconstitutional—and the two-year anniversary of his opinion in Windsor v. United States, finding the federal Defense of Marriage Act unconstitutional—Justice Kennedy today wrote the opinion in Obergefell v. Hodges, finding state bans on same-sex marriage unconstitutional, and securing full marriage equality for gays and lesbians across America.

What’s more, he swung for the fences, rejecting Chief Justice Roberts’s judicial minimalism to write a sweeping 5-4 opinion that reads like a manifesto in favor of same-sex marriage—ironically using many conservative arguments for marriage to do so.

The majority opinion in Obergefell is 28 pages long. Ten pages tell the stories of the case’s plaintiffs, and the history of the debate about marriage equality—already an unusual proportion of humanity to legalese. The next eight pages are about why marriage is a fundamental right, regardless of the genders of those getting married. As Justice Scalia, in particular, complained, they are filled with sweeping statements about the importance and meaning of marriage.

In other words, 18 out of the opinion’s 28 pages are a kind of doctoral thesis on the nature and importance of marriage. Only the last 10 engage in the typical, legalistic way with Supreme Court precedence and 14th Amendment jurisprudence.

To be sure, those 10 pages do adequately situate the case in its constitutional context, engaging with other cases extending marriage to previously excluded groups: Loving v. Virginia (mixed-race couples), Turner (inmates), and Zablocki (deadbeat dads). It makes a strong (and unusual, though not for Justice Kennedy) case that the two clauses of the 14th Amendment—guaranteeing equal protection and due process—are interlocked. And it responds to the dissenters’ concern that the Supreme Court is cutting off legislative debate, noting that that debate has gone on for many years already and the court’s role is to protect fundamental rights.

But it is the first 18 pages of the opinion that will be remembered in history—which, surely, is what Justice Kennedy had in mind.

Those pages are filled with “money lines” that can fill the Facebook pages of LGBT people and their allies. For example, consider Justice Kennedy’s four principles for why the right to marry is fundamental:

First, “The nature of marriage is that, through its enduring bond, two persons together can find other freedoms, such as expression, intimacy, and spirituality.” Thus defined (as opposed, say, to “complementarity” or other religiously-derived notions), the nature of marriage obviously extends to all people, regardless of gender or sexual orientation.

Second, “the right to marry is fundamental because it supports a two-person union unlike any other in its importance to the committed individuals.” Here, too, that is true for gay as well as straight couples. “As this Court held in Lawrence,” Kennedy wrote, citing himself, “same-sex couples have the same right as opposite-sex couples to enjoy intimate association.”

“A third basis for protecting the right to marry,” Kennedy continued, “is that it safeguards children and families and thus draws meaning from related rights of childrearing, procreation, and education.”

While this is usually a conservative talking point, Kennedy observed that “as all parties agree, many same-sex couples provide loving and nurturing homes to their children, whether biological or adopted.” Thus, “excluding same-sex couples from marriage thus conflicts with a central premise of the right to marry.”

Finally, Justice Kennedy wrote, “marriage is a keystone of our social order.” Enabling same-sex couples to marry strengthens, rather than weakens, marriage in general.

These four principles are a remarkable example of philosophical jujitsu, turning conservative arguments against conservatives. They essentially argue that marriage is important (conservative), and therefore it should be extended to all (liberal). Not coincidentally, this is much how the conservative same-sex marriage advocate Theodore Olson has framed the issue in numerous court cases and essays.

Justice Kennedy’s four principles are also a remarkable example of judicial writing. Justice Scalia called it “a style that is as pretentious as its content is egotistic.” And in a way, the criticism is warranted—Justice Kennedy is writing a broad philosophical treatise, not just a judicial opinion.

This continues when he moves on to the other central issues in the case.

Justice Scalia, for example, shockingly said that only marriages protected in 1868 (when the 14th Amendment was ratified) are protected today, a radical originalism that would allow states to ban mixed-race marriages, or allow women’s rights to be subsumed by their husbands (part of “coverture,” long a fundamental part of traditional marriage).

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Noting these evolutions of marriage, Justice Kennedy concludes, “If rights were defined by who exercised them in the past, then received practices could serve as their own continued justification and new groups could not invoke rights once denied.”

That is as succinct and clear a refutation of originalism as I have ever read.

And when Justice Kennedy turns to the religious objections some have to same-sex marriage, he again uses soaring tones: “Many who deem same-sex marriage to be wrong reach that conclusion based on decent and honorable religious or philosophical premises, and neither they nor their beliefs are disparaged here. But when that sincere, personal opposition becomes enacted law and public policy, the necessary consequence is to put the imprimatur of the State itself on an exclusion that soon demeans or stigmatizes those whose own liberty is then denied. Under the Constitution, same-sex couples seek in marriage the same legal treatment as opposite-sex couples, and it would disparage their choices and diminish their personhood to deny them this right.”

That statement is too long for a bumper sticker, but it, too, is a considered articulation of the difference between religious and civil marriage.

Finally, Justice Kennedy’s ultimate conclusion seems intended to be the final word on marriage equality, and to seal his legacy as well. And it is a deserved summation of two decades of his own evolution on this fundamental question of civil rights:

No union is more profound than marriage, for it embodies the highest ideals of love, fidelity, devotion, sacrifice, and family. In forming a marital union, two people become something greater than once they were. As some of the petitioners in these cases demonstrate, marriage embodies a love that may endure even past death. It would misunderstand these men and women to say they disrespect the idea of marriage. Their plea is that they do respect it, respect it so deeply that they seek to find its fulfillment for themselves. Their hope is not to be condemned to live in loneliness, excluded from one of civilization’s oldest institutions. They ask for equal dignity in the eyes of the law. The Constitution grants them that right.

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