Despite Grant's victories and the success of the Union blockade, Northern enthusiasm waned in 1864 as the war dragged on, casualties mounted, and families lost loved ones to battle wounds and disease. Still exasperated and impatient with his commanding officers, Lincoln finally promoted Grant to commanding officer of the U.S. Army. Grant invaded Virginia in May and fought a series of bloody battles against Lee's Army of Northern Virginia. Slowly but steadily, Grant pushed Lee down to the vicinity of Richmond, but Union troops were thrown back after making a ferocious assault at the Battle of Cold Harbor. After this defeat, Grant ordered his army to dig in and reinforce its position. On June 20, his army laid siege to the city of Petersburg, a rail center just south of Richmond. Although Grant had lost more than fifty thousand troops in the summer of 1864, the Army...