President Abraham Lincoln, bidding to gain the upper hand in the Civil War, issued Proclamation 104 on Sept. 15, 1863, suspending the writ of Habeas Corpus throughout the United States. He wrote in his proclamation that "this suspension will continue throughout the duration of the said rebellion, or until this proclamation shall, by a subsequent one to be issued by the President of the United States, be modified or revoked."
Such a writ is a right under U.S. law allowing a prisoner to petition to be brought before the courts to determine if that person's continuing detention by authorities is lawful. Constitutionally, it can be suspended only in extraordinary circumstances such as ensuring public safety in times of rebellion or invasion. Lincoln's move to suspend the writ was controversial at the time.