By 1864 it was becoming increasingly more difficult to conscript enough able-bodied men to fight for either the North or South. Before the war began in early April of 1861, the United States Army had around 16,400 officers and men. On April 9, 1861 a call was made for the District of Columbia to muster ten companies of militia. There was some resistance as evidenced by one company of 100 men: two officers, one sergeant, one corporal, one musician and ten privates refused to muster.
Less than a week later, President Lincoln called for 75,000 militiamen to serve three months. By May he was calling for 500,000 to serve three years. In 1862 there were calls for 300,000 to serve three years and later that year another 300,000 to serve for nine months. As the war continued unabated, calls for more enlistments were issued. Some would re-enlist after their term of service had expired. Even with a large numbers of troop already assembled, Lincoln made a special plea in 1863 and 1864, first to Maryland, Pennsylvania, Ohio and West Virginia.