Although a legendary milestone in the long fight for racial equality in the United States of America, the Emancipation Proclamation was in fact a cynical political gambit. By freeing slaves in all those areas still in open rebellion against the government in Washington D.C. – more than three quarters of the four million black slaves in America at that time – Lincoln hoped to encourage rebellions and desertions among the slave population, splitting the Confederate forces and hamstringing their economy. He made no such gesture for any of the slave holding states on his side of the Civil War – but he doubt realised that come the end of the war, he had created conditions whereby they too would expect to be freed.
The overall effects of the Emancipation were more or less as Lincoln had hoped, although less drastic in their effects than he might have wished. There were plentiful desertions by slaves; conversely, there were also desertions by Union troopers who felt that this was not what they had signed up for.