The Ku Klux Klan opposed others.
The Ku Klux Klan ( KKK ) , or simply the Klan , is the name of three distinct movements in the United States that have advocated extremist reactionary currents such as white supremacy , white nationalism , anti-immigration , and , especially in later iterations , Nordicism , anti-Catholicism , and antisemitism . Historically the KKK used terrorism , both physical assault and murder , against groups or individuals whom they opposed . It was rooted in local Protestant communities and opposed Catholics and Jews , and stressed its opposition to the Catholic Church at a time of high immigration from mostly Catholic nations of southern and eastern Europe .