Actually Lincoln was a pragmatist and had to deal with prioritizing things accordingly.
On August 22, 1862, just a few weeks before signing the Proclamation and after he had already discussed a draft of it with his cabinet in July, he wrote a letter in response to an editorial by Horace Greeley of the New York Tribune which had urged complete abolition. Lincoln differentiates between "my view of official duty"—that is, what he can do in his official capacity as President—and his personal views. Officially he must save the Union above all else; personally he wanted to free all the slaves:
I would save the Union. I would save it the shortest way under the Constitution. The sooner the national authority can be restored; the nearer the Union will be "the Union as it was." If there be those who would not save the Union, unless they could at the same time save slavery, I do not agree with them. If there be those who would not save the Union unless they could at the same time destroy slavery, I do not agree with them. My paramount object in this struggle is to save the Union, and is not either to save or to destroy slavery. If I could save the Union without freeing any slave I would do it, and if I could save it by freeing all the slaves I would do it; and if I could save it by freeing some and leaving others alone I would also do that. What I do about slavery, and the colored race, I do because I believe it helps to save the Union; and what I forbear, I forbear because I do not believe it would help to save the Union. I shall do less whenever I shall believe what I am doing hurts the cause, and I shall do more whenever I shall believe doing more will help the cause. I shall try to correct errors when shown to be errors; and I shall adopt new views so fast as they shall appear to be true views. I have here stated my purpose according to my view of official duty; and I intend no modification of my oft-expressed personal wish that all men everywhere could be free.
On August 22, 1862, just a few weeks before signing the Proclamation and after he had already discussed a draft of it with his cabinet in July, he wrote a letter in response to an editorial by Horace Greeley of the New York Tribune which had urged complete abolition. Lincoln differentiates between "my view of official duty"—that is, what he can do in his official capacity as President—and his personal views. Officially he must save the Union above all else; personally he wanted to free all the slaves:
I would save the Union. I would save it the shortest way under the Constitution. The sooner the national authority can be restored; the nearer the Union will be "the Union as it was." If there be those who would not save the Union, unless they could at the same time save slavery, I do not agree with them. If there be those who would not save the Union unless they could at the same time destroy slavery, I do not agree with them. My paramount object in this struggle is to save the Union, and is not either to save or to destroy slavery. If I could save the Union without freeing any slave I would do it, and if I could save it by freeing all the slaves I would do it; and if I could save it by freeing some and leaving others alone I would also do that. What I do about slavery, and the colored race, I do because I believe it helps to save the Union; and what I forbear, I forbear because I do not believe it would help to save the Union. I shall do less whenever I shall believe what I am doing hurts the cause, and I shall do more whenever I shall believe doing more will help the cause. I shall try to correct errors when shown to be errors; and I shall adopt new views so fast as they shall appear to be true views. I have here stated my purpose according to my view of official duty; and I intend no modification of my oft-expressed personal wish that all men everywhere could be free.
Source: http://en.wikipedia.org/wiki/Abraham_Lincoln_and_slavery