Confederate-held Vicksburg fell to the Union after a forty-seven day siege on July 4, 1863 due to Lieutenant General John C. Pemberton's failure to maintain options. Pemberton's decisions in late 1862 and early 1863 diminished the capability of his force. In May 1863, when Union Major General Ulysses S. Grant crossed the Mississippi River, Pemberton's army could not transition from a static defensive posture to a more mobile form. Pemberton's mistakes centered around his emphasis on terrain rather than the enemy, as well as his failure to adapt as the conditions changed. In these blunders, he ceded control of tempo and the momentum to the enemy. Rather than setting conditions to seize the initiative in the event of a Federal crossing of the Mississippi River, Pemberton chose to disperse his forces to the periphery of his department and hold his territory in its entirety. He sacrificed his ability to mobilize, mass, and maneuver and in return gained a thin line of protection around the boundary of his department. This form of defense taxed his logistics assets, caused supply shortages in food and ammunition, and destroyed his rail and roads all prior to the start of Grant's attack. By the time the Union offensive did come, Pemberton had neither the option to attack nor flee.

Approved for public release; distribution is unlimited. The opinions and conclusions expressed herein are those of the student author and do not necessarily represent the views of the US Army Command and General Staff College or any other government agency. (References to this study should include the foregoing statement.)