Vicksburg's fall gave Union forces control of the Mississippi River and split the Confederacy. By that time, Grant's political sympathies fully coincided with the Radical Republicans' aggressive prosecution of the war and emancipation of the slaves. The success at Vicksburg was a morale boost for the Union war effort. When Stanton suggested Grant be brought back east to run the Army of the Potomac, Grant demurred, writing that he knew the geography and resources of the West better and he did not want to upset the chain of command in the East.