"Ku Klux got after some Catholics one time"
KKK parade in Virginia
Public DomainKKK parade in Virginia

 The Ku Klux Klan, often abbreviated to KKK, is the name of a far-right racist hate group in the United States. They attacked and murdered African-Americans, Jews and other minorities, and also intimidated and opposed Roman Catholics and labor unions.

"The Klan" originated in the Southern states, where it has continued to operate, on and off, to this day. It was first founded in 1865 by Tennessee veterans of the Confederate Army. Klan groups then spread throughout the South. Its purpose was to restore white supremacy in the aftermath of the American Civil War. They wore iconic white costumes consisting of a robe, a mask, and a conical hat.

At its peak in the mid-1920s, the organization comprised about 15% of America's population (approximately 4–5 million men); but the Klan's popularity fell during the Great Depression and World War II.  Today, researchers estimate that there may be around 5,000 to 8,000 Klan members.