What outlawed slavery in the entire country?

The Thirteenth Amendment

Explanation:

It abolished slavery and involuntary servitude, except as punishment for a crime.

was a long, primarily nonviolent series of events to bring full civil rights and equality under the law to all americans. the era has had a lasting impact on united states society, in its tactics, the increased social and legal acceptance of civil rights, and in its exposure of the prevalence and cost of racism. in the south violence and fraud in southern elections from 1868 to 1876, which had reduced black voter turnout and enabled southern white democrats to regain power in state legislatures across the south

this is a good question! i'll do some research and come back when i have the answer!