The Union capture of Vicksburg, the last Confederate stronghold on the Mississippi, was vital, and would split the Confederacy in two. Lincoln, however, appointed McClernand for the job, rather than Grant or Sherman. Halleck, who retained power over troop displacement, ordered McClernand to Memphis, and placed him and his troops under Grant's authority. On November 13, 1862, Grant captured Holly Springs and advanced to Corinth. Grant's plan was to march south to Jackson, and attack Vicksburg overland, while Sherman would attack Vicksburg from Chickasaw Bayou. However, Confederate cavalry raids on December 11 and 20, 1862, broke Union communications and recaptured Holly Springs, preventing Grant and Sherman from converging on Vicksburg. Grant observed sabotage by civilians who had feigned loyalty and complained: "Guerrillas are hovering around in every direction." On December 29, a Confederate army led by Lieutenant General John C. Pemberton repulsed Sherman's direct approach ascending the bluffs to Vicksburg at Chickasaw Bayou. McClernand reached Sherman's army, assumed command, and independently of Grant led a campaign that captured Confederate Fort Hindman.