Frustrated with continued resistance to civil rights for freedmen in the former Confederate states where black citizens were being harassed and imprisoned in state courts under the control of white conservatives, the United States Congress passed the Habeas Corpus Act of 1867. This far-reaching act widened appellate opportunities so that federal circuit courts, and ultimately the United States Supreme Court, could hear writs against false imprisonment by state courts for the first time in constitutional law. Ironically, the most famous immediate case heard the next year in the Supreme Court came not from a freeman wrongly imprisoned in a state court but from a white Confederate sympathizer named William McCardle, imprisoned by a federal court in Mississippi. (By John Osborne)
Mark Tushnet, Mark Graber, and Sanford Levinson (eds.), The Oxford Handbook of the U. S. Constitution (New Yor: Oxford University Press, 2015), 684.