Mr. P said:
That was what I was trying to get at earlier. Lincoln was a politician, a damned fine one. The Union was losing battle after battle. When they came close to winning something, the generals wouldn't follow up. The Copperheads were getting more and more belligerent about the war, after all, they couldn't afford to buy their way out of the draft, but they knew they would be competing as immigrants, with the blacks if they were freed. It wasn't that they were FOR slavery, just didn't think it was worth dying for and then paying for again in the job market.
Now the abolitionists, they sure did think it was worth lots of folks dying for. They were extreme, moreso than any other group. They were also as a whole, more educated and wealthier than average and they truly believed they knew what was best for everyone. They also held sway in the press. (Remind you of any group today?) Well Lincoln needed some good press, in a big way. So he followed up a victory, with the Emancipation Proclamation. Now I think it's a good thing, but it was very calculated at the time.