But Scalia may have outdone himself in his 2013 dissent in the case of United States v. Windsor. For years, he has been unrelenting in opposing constitutional protections for gays and lesbians. In his 2003 dissent in Lawrence v. Texas, Scalia warned darkly that the Court majority “has largely signed on to the so-called homosexual agenda” even though “many Americans do not want persons who openly engage in homosexual conduct as partners in their business, as scoutmasters for their children, as teachers in their children’s schools, or as boarders in their homes.”

In Windsor, the Court’s majority struck down Section 3 of the Defense of Marriage Act, which forbade federal recognition of same-sex marriages that were legal under state law. In an opinion by Justice Anthony Kennedy, the majority concluded that its “purpose and effect” were “to disparage and to injure those whom the State, by its marriage laws, sought to protect in personhood and dignity.”

The opinion was the triumph of the “homosexual agenda” Scalia had denounced. The majority opinion, Scalia wrote in a slashing dissent, meant the end of state laws restricting marriage to opposite-sex couples:

The real rationale of today’s opinion, whatever disappearing trail of its legalistic argle-bargle one chooses to follow, is that DOMA is motivated by “‘bare ... desire to harm’” couples in same-sex marriages. How easy it is, indeed how inevitable, to reach the same conclusion with regard to state laws denying same-sex couples marital status.

In retrospect, Scalia’s choice of words may have been a mistake.

Many dissents seek to limit the majority opinion, suggesting ways that lower courts can work around it. Chief Justice John Roberts offered one such attempt in Windsor, suggesting that “the Court does not have before it, and the logic of its opinion does not decide, the distinct question whether the States, in the exercise of their ‘historic and essential authority to define the marital relation’ may continue to utilize the traditional definition of marriage.”

Scalia and his vivid language, however, grabbed the attention of press, public—and, it turned out, lower-court judges. With stunning swiftness, federal district judges have heard and decided challenges to state same-sex marriage bans, and by May 2014, a dozen judges had struck them down—first in Utah; then in rapid succession, Ohio, Illinois, Virginia, Kentucky, and even Texas. Judges young and old, male and female, gay and straight, Republican and Democrat, read Windsor and saw in it a logic that doomed state efforts to confine marriage to its “traditional” function as a union of man and woman. And some of what they read was not in the majority opinion but in Scalia’s dissent. In fact, about half of the opinions explicitly cited Scalia’s words. A representative passage by Judge Timothy Black, a district judge in Ohio, states:

And now it is just as Justice Scalia predicted—the lower courts are applying the Supreme Court's decision, as they must, and the question is presented whether a state can do what the federal government cannot—i.e., discriminate against same-sex couples ... simply because the majority of the voters don't like homosexuality (or at least didn't in 2004). Under the Constitution of the United States, the answer is no ....

No words Scalia would write in the October 2013 term would be remotely as important or influential as his 2012 “prediction.” That’s because disguised within the flamboyant rhetoric, he had made an important legal concession.