The correct answer is “they left application and enforcement of civil rights in the hands of state governments, which stripped away rights for southern blacks.”
The united states v. Cruikshank was a case decided by the US Supreme Court in 1876 about an armed white militia attacked and killed about 200 African Americans. When the case reached the US Supreme Court the Court decided that the Bill of Rights was not applied to the states this way the Court basically led to the allowance of violence and deprivation of rights against newly freed slaves and stripped away rights for southern blacks.