Shortly after the president announced the nomination, rumors circulated that as a young lawyer in Alabama, Black had been a member of the Ku Klux Klan. The N.A.A.C.P. asked for an investigation, but a Senate Judiciary subcommittee rammed the nomination through to the full committee after two hours of consideration. One Democratic senator, William Dieterich of Illinois, accused other senators of trying to “besmirch” Black’s reputation. As the historian William E. Leuchtenberg described the scene in a fascinating 1973 article, “Dieterich’s tirade nearly resulted in a fist fight” as another Democratic senator charged at him.

Supreme Court nominees did not ordinarily appear at their confirmation hearings in those days, but Black’s supporters said he had assured them that he had never joined the Klan. The full committee moved the nomination to the Senate floor. Black was confirmed by a vote of 63 to 16, and the new justice and his wife set sail for a European vacation.

In mid-September, while Black was in Paris and the court was getting ready to open a new term, The Pittsburgh Post-Gazette published the first of six articles conclusively linking him to the Klan. Soon, the country was in an uproar. The Klan stood for violence not only against African-Americans but also against Catholics, who were prominent among Roosevelt’s most loyal supporters. Catholic members of Congress demanded that Black step down. Senator David I. Walsh, a Democrat and a former governor of Massachusetts, charged that “Black obtained his nomination and confirmation by concealment and thereby deceived the president and his fellow senators, especially the latter.” A Gallup poll found that 59 percent of the public believed Black should resign if the charge was true.

On his return to the United States, Black gave a national radio address, as unusual then as Brett Kavanaugh’s appearance on Fox News was this month. Carried by 300 stations on three radio networks, the speech attracted the second-biggest audience of the decade, outdone only by the abdication speech of King Edward VIII. Black conceded that he had joined the Klan and said he had resigned before he became a senator. He neither explained his decisions nor apologized for his membership. In fact, in Professor Leuchtenberg’s account, “He spent the first third of his remarks cautioning against the possibility of a revival of racial and religious hatred, but he warned that this might be brought about not by groups like the Klan but by those who questioned his right to be on the Supreme Court.”

The national press excoriated the speech as thoroughly inadequate, but Roosevelt discerned accurately that “it did the trick,” as he told his confidant James Farley. A new Gallup Poll showed that a majority of Americans now believed that Black should not resign. He was on the bench when the new term opened three days after his speech, went on to serve for 34 years, one of the longest Supreme Court tenures, before retiring in 1971 at the age of 85.