“This gathering heard more speeches, listened to more spoken words, experienced more fistfights, spent more time in committee, and witnessed more demonstrations than any other such assemblage in history,” Mr. Murray wrote.

Passions crested when some delegates proposed that the platform include the words, “We pledge the Democratic Party to oppose any effort on the part of the Ku Klux Klan or any organization to interfere with the religious liberty or political freedom of any citizen, or to limit the civic rights of any citizen or body of citizens because of religion, birthplace or racial origin.” The proceedings of the convention, which ran to 1,315 pages, report: “Resounding cheers, applause, rising demonstrations, delegates standing on chairs waving hats, the chairman vainly rapping his gavel for order; disorder in the galleries; cries of ‘Get out,’ ‘Say it again.’”

Senator Oscar Underwood of Alabama, who supported the anti-Klan plank, was denounced by the Klan as “‘the Jew, jug and Jesuit candidate’ — the ‘jug’ reference meant to disparage Underwood’s opposition to Prohibition,” Terry Golway wrote in “Machine Made: Tammany Hall and the Creation of Modern American Politics.”

The fight went on for hours, and ultimately, the Klan and its allies prevailed in the platform fight as a resolution to condemn them by name lost by less than one vote — 543 and three-twentieths votes to 542 and seven-twentieths votes. (Some delegates could cast fractional votes.)

Neither Governor Smith nor Mr. McAdoo came close to getting two-thirds of the delegates needed for the nomination. The compromise candidate, John W. Davis, got only 29 percent of the vote when he ran in the general election against President Calvin Coolidge.

Four years later, Governor Smith won the Democratic nomination, but the Klan awaited him as he crossed the country, burning crosses and spreading lies. “The Grand Dragon of the Realm of Arkansas, writing to a citizen of that state, urges my defeat because I am a Catholic,” he said in a speech. “During all of our national life, we have prided ourselves throughout the world on the declaration of the fundamental American truth that all men are created equal.”

He lost to Herbert Hoover.