From the West Point History of the Civil War, p. 36 which is quoting Richard McMurray: "Over 80 percent of the military-age population in 1860 lived in the states and territories that were to remain loyal to the Federal government. New York State's military population alone was three-fourths that of the entire Confederacy. New York, Massachusetts and Vermont alone could have fielded an army that outnumbered the military-age population of the eleven Rebel states by 31,587 men. When those eastern Yankees needed to rest from fatigues of war, they could have been replaced by a force from Illinois, Indiana and Ohio that exceeded total Confederate strength by 35,662 men. Pennsylvania's half a million military-age men would have provided adequate replacements for any casualties, and the military-age men in the other sixteen northern states could gone about their normal business." The four border states did not split entirely in favor of the United States. But neither did Virginia, Tennessee or Alabama split entirely in favor of the Confederacy. But the situation is even more severely in favor of the United States than these numbers state. The United States had access to two more demographic pools, the African-Americans in the south, and the Canadians in the north, especially Quebecois. It did not matter particularly how many people in those labor pools were willing to serve as soldiers and sailors. It did matter how many were willing to work in the United States or serve as pioneers in the advancing United States armies. But the situation was worse even than that. The military-age population of the north was so large because immigration was tilted in favor of single young men. But immigration did not end in 1860. Most Europeans had countrymen in the northern United States, so when immigration resumed in 1863, the United States could refresh its armed forces and labor pool. People in the United States military and in Britain could figure out that the United States was going to win with some basic computations.