What could the North have done to stop the South from using black codes.

Answer 1

WARNING: TERRORISM AND MURDER

Many so-called Black Codes were unconstitutional under the 13th, 14th, and 15th amendments. The North was heavily involved in Reconstruction efforts post-civil war to reunite the country. Military protection of Black voters meant that Black representatives were elected to represent the interests of their constituents. Many see this as having been a huge step in the right direction. Frustratingly, this would not last. When the North pulled out, White Supremacists seized power through terrorist campaigns, mob violence, and public murders (called lynchings) to keep Black people from voting.

Without close federal oversight, White Supremacists wherever they were felt free to act as they pleased with no repercussions. White supremacists in every avenue of power used their power to instate the Black Codes you're asking about, which restricted the rights of non-white people in many areas of life. Perhaps obviously, it was easier to pass racist laws if Black people did not vote. A student of history may wonder, for example, why perpetrators of lynchings were not brought to justice. Well, too often, members of the police force were in on the violence, because they were white supremacists too. In this way, racism was not simply interpersonal violence but became codified in the law and built into the structures of society.

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