Historians have largely agreed that Pemberton should shoulder the blame for the poor Confederate performance during the Vicksburg campaign. General consensus exists among American Civil War historians that Pemberton proved a confused, indecisive, and incompetent commander and his poor leadership led to the Confederate defeat. However, an examination of the Vicksburg campaign conducted at the operational level of war shows that throughout the campaign, Pemberton led a capable and competent defense not just of Vicksburg, but of the Mississippi Department he commanded. He relied on an operational approach that involved fighting from prepared defensive positions in favorable terrain deep in his own territory and anchored by natural obstacles. To attack such a position, Pemberton knew an opponent would need a large force operating over an extended line of communications (LOC). Pemberton intended to interdict his opponent's LOC using a strong cavalry force, thus preventing the enemy from achieving the offensive momentum necessary to break through Vicksburg's defenses. This was a sound operational approach. However, it failed because of an ineffective Confederate command structure that, among other failures, denied Pemberton the resources, particularly adequate cavalry forces, required to implement his operational approach.