But the Klan was easily at its most popular in the United States during the 1920s, when its reach was nationwide, its members disproportionately middle class, and many of its very visible public activities geared toward festivities, pageants, and social gatherings. In some ways, it was this superficially innocuous Klan that was the most insidious of them all. Packaging its noxious ideology as traditional small-town values and wholesome fun, the Klan of the 1920s encouraged native-born white Americans to believe that bigotry, intimidation, harassment, and extralegal violence were all perfectly compatible with, if not central to, patriotic respectability.

The Ku Klux Klan had been defunct for nearly a half-century when William J. Simmons decided to revive the organization in the fall of 1915. A resident of Atlanta, Simmons worked for a fraternal benefit society called the Woodmen of the World, and he already belonged to more than a dozen clubs and churches. But he had dreamed for years about founding a fraternal order himself someday, and with D.W. Griffith’s cinematic paean to the Klan, The Birth of a Nation, scheduled to debut in Atlanta, the inspiration and the timing seemed right. On Thanksgiving night, after riding with about 15 other men in a rented tour bus to a large granite formation outside of the city known as Stone Mountain, Simmons lit a wooden cross aflame and announced the rebirth of the Knights of the Ku Klux Klan.

Advertised by Simmons in Atlanta newspapers as “The World’s Greatest Secret, Social, Patriotic, Fraternal, Beneficiary Order” and a “High Class Order for Men of Intelligence and Character,” the new Klan floundered for several years. It had attracted just a few thousand members by the spring of 1920, when Simmons hired Mary Elizabeth Tyler and Edward Young Clarke as publicity agents and promoters for the group. Tyler and Clarke divided the entire country into what amounted to sales territories and they sent more than 1,000 solicitors into the field to recruit members whose $10 membership fee for the Klan went in part to the solicitors as commission.

Tyler and Clarke’s strategies were immensely successful, swelling the national membership of the Klan to over 100,000 within a matter of months. In 1921, a newspaper exposé detailed more than 100 acts of Klan-sponsored vigilante violence and prompted a congressional investigation, but the ensuing publicity only made the Klan stronger. It claimed more than 1 million members by early 1922. Internal squabbles and power struggles led to the ouster of Simmons from his leadership post later that year, and he was replaced by a dentist from Texas named Hiram Evans. Organizational infighting and external opposition notwithstanding, the Klan continued to grow. By 1925, it had anywhere from 2 million to 5 million members and the sympathy or support of millions more.