After President Lincoln removed George B. McClellan from the position of general in chief, Lincoln and Secretary of War, Edwin Stanton had attempted to manage the war without a general in chief. In the wake of the failed Peninsula campaign they understood that they needed a professional military general to fill the vacant position. On July 11, 1862, Lincoln named Major General Henry W. Halleck to be the Union;s general in chief. He assumed the position on July 23, 1862.