What government act put an in to the ku klux klan activity

If "enforcement" doesnt work, fill in the blank with "Force" (it sounds dumb but I just got it wrong using enforcement

because of its location and commercial importance, atlanta was used as a center for military operations and as a supply route by the confederate army during the civil war. therefore, it also became a target for the union army. general william tecumseh sherman and his troops captured the city in 1864.