With the ascendancy of Ulysses S. Grant in late 1863, the command tone of the United States Army underwent a dramatic change. While Grant's predecessor George McClellan had been overly cautious about committing troops and resources to fight the South, Grant held the philosophy that a war fought for total ends required total means.
Philip Sheridan set about reorganizing the army to reflect Grant's new style. During the last six months of the war, he relieved three generals of their commands because of their inability to follow his orders precisely. William Averell, Alfred Torbert and Gouverneur Warren found themselves and their careers casualties of Sheridan's intense determination to bring an end to the hostilities.
Only Ranald S. Mackenzie managed to survive Sheridan's search for effective leaders, proving himself the ideal subordinate.