WITH gay marriage litigation moving forward at warp speed — federal judges have struck down five state bans on same-sex marriage since December — we may soon witness one of the worst shouting matches in Supreme Court history. Passions were already running high last June, when a divided court struck down federal, but not state, laws defining marriage exclusively as a relationship between a man and a woman. Justice Antonin Scalia denounced the majority opinion, which cited the demeaning and humiliating effects of the Defense of Marriage Act, as “legalistic argle-bargle” lacking any basis in our constitutional tradition. Writing for the five justices in the majority, Justice Anthony M. Kennedy countered that the assault on human dignity should be decisive in condemning the statute as unconstitutional.

In making this “dignitarian” move, Justice Kennedy relied principally on his two earlier pathbreaking opinions supporting gay rights, in 1996 and 2003. He did not link his guiding philosophy to the broader principles hammered out during the civil rights revolution of the 1960s. Yet that constitutional legacy would strongly support any future Supreme Court decision extending Justice Kennedy’s reasoning to state statutes discriminating against gay marriage. Indeed, the court should reinforce its dignitarian jurisprudence by stressing its roots in the civil rights revolution — and thereby demonstrate that it is Justice Scalia, not Justice Kennedy, who is blinding himself to the main line of constitutional development.

Consider the great speeches made 50 years ago today as the Senate began its decisive debate on the Civil Rights Act of 1964. The bill’s floor managers were the Democrat Hubert H. Humphrey and the Republican Thomas H. Kuchel. As they surveyed the scene on March 30, 1964, it was far from clear that they had the 67 votes required to break a filibuster led by Southern senators. So they were determined to make their case to the larger public and mobilize popular support for a sustained effort to win a cloture vote.

As The Washington Post reported at the time, the two floor leaders dominated the first day’s proceedings with elaborate presentations that set the stage “for a serious no-nonsense debate” on the fundamental issues. Humphrey began with a remarkable three-and-a-half-hour speech that introduced the central theme of humiliation by comparing two travel guidebooks: one for families with dogs, the other for blacks. “In Augusta, Ga., for example,” Humphrey noted, “there are five hotels and motels that will take dogs, and only one where a Negro can go with confidence.” He argued that if whites “were to experience the humiliation and insult which awaits Negro Americans in thousands and thousands of such places, we, too, would be quick to protest.” Kuchel followed up with a second major presentation, emphasizing the “urgency” of ending the “humiliating forms of discrimination” confronting blacks.