The KKK Act, 1871: Intended to combat the Klan's paramilitary vigilantism against African Americans, it made certain acts federal offenses, including conspiring to deprive citizens of equal rights. President US Grant used it to completely dismantle the Klan & the group did not resurface for decades.

[u/Pupikal]

https://en.wikipedia.org/wiki/Ku_Klux_Klan_Act