On July 2, 1863, the second day of fighting at Gettysburg, Maj. Gen. Daniel E. Sickles, in a controversial interpretation of his orders, advanced his men beyond the established Union line, exposing his flanks to a potentially devastating Confederate attack. Shortly after being reprimanded by his commander, Maj. Gen. George G. Meade, for endangering the entire Union Army, Sickles was hit by a cannonball. He returned to Washington, D.C., with his leg...