John Merryman is a Maryland citizen who supports the Confederates. Charged with assisting the rebellion, he is arrested. Chief Justice Roger Taney issues a writ of habeas corpus, requiring the military commander to bring Merryman before the U.S. Supreme Court. The commander refuses because of President Abraham Lincoln’s executive order suspending habeas corpus (a legal procedure through which a prisoner can challenge his detention).
Taney writes an opinion condemning Lincoln’s order as unconstitutional and declaring that Merryman is free. Taney sends a copy of his opinion to Lincoln, who ignores it and later goes before Congress to defend his right to suspend habeas corpus.