The battle of Resaca in May 1864 represents a series of firsts: the first major battle of the Atlanta Campaign, the first occasion in Georgia in 1864 of Confederate and Federal armies in their entirety facing one another across a field of battle, and the first major encounter between Joseph E. Johnston and William T. Sherman as army field commanders. The two-day battle of Resaca proved to be an experience for Sherman that would cause him to alter the patterns of strategy and tactics in the campaign that followed. Eventually, Yankees would capture Atlanta in September, and the timing of Atlanta's fall would have a profound political impact on the reelection of an American president and subsequently, the outcome of the war.