Eighty years ago, in mid March 1924, Edward Young Clarke, an advertising executive in the state of Louisiana, pled guilty in federal court to violating the Mann Act (an anti-prostitution measure enacted in 1910). The fact that he had been caught taking his mistress across state lines, however, was just the tip of this federal case.

Why was Clarke a wanted man? He was no mere advertising executive. He was an entrepreneur who believed in the tenets of the Ku Klux Klan -- which had been resurrected by "Colonel" William S. Simmons in 1915 -- and he took its anti-Jewish, anti-African American, and anti-Catholic tenets to heart. At the same time, he also liked to turn a profit. In 1920 he agreed to aggressively increase membership in the Klan in return for a share of the membership dues. And he was incredibly successful: over 1 million members signed up in short order.

In 1922, Louisiana Governor John M. Parker sent J. Edgar Hoover (then Assistant Director of the Bureau of Investigation) a heartfelt message that was personally delivered by a New Orleans newspaper reporter. Please help, it said, the Ku Klux Klan has grown so powerful in my state that it effectively controls the northern half. It has already kidnapped, tortured, and killed two people who opposed it…and it has threatened many more.

How could the Bureau investigate? At the time, of course, federal laws were few and the Bureau did not have authority to investigate. KKK cross-burnings and murders were a state matter. But Governor Parker petitioned President Harding to act under the constitutional guarantee that the federal government would protect the states from domestic violence (Article 4, Section 4). The President agreed, and the Bureau promptly sent Agents to investigate, even though it would likely have to turn its evidence over to state governments to prosecute the cases.

What did the FBI find? It found that the Klan was wielding great political power throughout the South as it fed off the prejudices of the day and instilled fear in millions. It found that Clarke’s campaign to increase Klan membership had been a resounding success. Membership had soared and so had the number of Klan groups in many different states.

On a more personal note, it found that "Imperial Kleagle"Clarke had lined his pockets with $8 of each $10 initiation fee he had secured…and that he was also netting tidy profits from his new-member sales of the Klan's bed-sheet regalia. It also found that he was using his wealth to lead a high life, including taking on a mistress…and it found he was crossing state lines with her.

Gotcha. Now this last was an interesting point. How about the Mann Act?, some enterprising Bureau lawyer suggested. That’s a federal law we can use in this case. Accordingly, Clarke was arrested the next trip he made with his mistress over a state line, leading to his guilty plea in federal court.

It was just the beginning of the Bureau’s fight to bring these early day domestic terrorists to justice.

Link: FBI History