For those who are ill-informed and think the Union were the white hat saviors of the black man and fighting a good vs evil battle over slavery....
Taken from
http://www.pbs.org/wgbh/aia/part4/4p2967.html:
"President Lincoln insisted that the war was not about slavery or black rights; it was a war to preserve the Union. His words were not simply aimed at the loyal southern states, however -- most white northerners were not interested in fighting to free slaves or in giving rights to black people. For this reason, the government turned away African American voluteers who rushed to enlist. Lincoln upheld the laws barring blacks from the army, proving to northern whites that their race privilege would not be threatened."
Not until the Emancipation Proclamation TWO YEARS INTO THE WAR did the North make a new, second objective of freeing slaves, and only those in southern states at that, leaving slavery intact in Union states.