THE EMANCIPATION PROCLAMATION
When he was elected president, Abraham Lincoln had no thought whatsoever of freeing the slaves; he repeatedly stated that he had no constitutional right to do that. However, on a practical level Lincoln realized that the continued existence of slavery in the South would make Northern victory harder; the existence of slavery allowed Southern landowners to leave their fields and fight in the Confederate army.
The Emancipation Proclamation was issued on January 1, 1863. The timing of this was a brilliant political move. Support for the war in the North had been waning; the Emancipation Proclamation gave Northerners a moral justification to continue fighting. This measure was received by different groups in predictable ways. Northern blacks were heartened by it, Southerners condemned it, and in Southern territories controlled by the Union army, slaves were actually freed. Many in England agreed with the proclamation; any last hopes that England might enter the war to aid the Confederacy were dashed at this point. Some whites in the North feared that ex-slaves would end up taking their jobs, and as a result, in the 1862 congressional elections Democrats picked up seats.
Blacks were not accepted into the Union army at the beginning of the war. After the Emancipation Proclamation many ex-slaves from Southern territories and free blacks from the North joined the Union army. By 1865, blacks made up almost 10 percent of the entire Union army. Black soldiers traditionally served in all-black units with white officers (the heroism of the 54th Massachusetts Infantry can be seen in the movie Glory).