April 27, 1861, President Abraham Lincoln instructs General Winfield Scott to suspend habeas corpus as necessary to keep vital transport and supply lines clear in Maryland. This action kicks off a legal dispute with the Supreme Court.
One month later, on May 25, 1861, John Merryman, a state legislator from Maryland, is arrested for attempting to hinder Union troops from moving from Baltimore to Washington during the Civil War and is held at Fort McHenry by Union military officials. His attorney immediately sought a writ of habeas corpus so that a federal court could examine the charges. However, because President Lincoln had suspended the right, the general in command of Fort McHenry refused to turn Merryman over to the authorities.