In 1876 Rutherford B. Hayes, a Republican, made a deal with the Democrats, that he would end reconstruction if they would let him be President of the United States. In this same year the Supreme Court ruled that only states, not the Fed, could prosecute violations of the Ku Klux Klan Act, a law meant to protect Black people from White violence. States refused to prosecute.
That was a rough year for Black Americans.
That year facilitated a swift slide back toward the America that existed before the civil war. The difference this time was that a constitutional amendment prevented slavery, so in its place rose up a system, both formal and informal, legal and/or practical, that pushed Black people back away from being considered Americans.
This period, from around 1890 up through the 1940’s, is called the “Nadir”.
The Nadir is considered not simply the low point in post slavery American race relations, but more so the low point in the lived experience of Black Americans. this is the time where it was normal for Black people who got “too successful” or even just sassy, to be publicly murdered.
This is the time period that most directly set the table for the racial America we have today. If you want to understand #blacklivesmatter, the Congressional Black Caucus, the NAACP, #oscarsowhite, or the whys and hows of the Civil rights Movement, you need to first understand the Nadir.