Even as Nathan Bedford Forrest’s Confederate cavalry was successfully harassing Ulysses Grant’s supply lines, Grant’s army was formally reorganized for the drive against Confederate held Vicksburg on the Mississippi River.
William Tecumseh* Sherman was given the Fifteenth Corps, Stephen Hurlbut was assigned the Sixteenth Corps, and John McClernand was assigned the Thirteenth Corps. The latter appointment ended any separate command for McClernand, who had been appointed by Lincoln as head of a second Union army to operate against Vicksburg.
Depriving McClernand of an independent command did little, however, to curb his personal and political rivalry with Grant. McClernand consistently attempted to undercut Grant’s popularity with the president and the War Department by often claiming Grant’s successes as those of his own.