Lincoln’s long struggle to find a commanding officer whose promises of success were supported by action ended with Ulysses S. Grant, whose victories in the West led to his appointment as general-in-chief of the Union army in March 1864. Grant coordinated offensives with Union commanders in other theaters of war, before taking to the field himself during the Overland Campaign in Virginia (May–June 1864). Although casualties were high on both sides, Grant refused to follow precedent and withdraw to rest his army. He instead pressed forward with flanking maneuvers against Lee, vowing to Secretary of War Edwin Stanton to continue the fight all summer if necessary.