The Colfax Massacre occurred in Colfax, Louisiana on April 13, 1873. Republicans had narrowly won the 1872 election to retain control of the state, but Democrats contested the results.
Fearful that white militias would attempt to take over local parish governments, Republican officeholders occupied the Colfax courthouse, while African Americans dug trenches outside to defend the building. White paramilitary groups attacked the group, and the ensuing gun battle resulted in more than 100 people dead; many African Americans were killed after they surrender.
Although federal charges were brought against several white insurgents, the Supreme Court later ruled in United States v. Cruikshank that the 14th Amendment only applied to state actions and offered no protections against acts by individual citizens. Read an overview in The Root.