Lincoln had absolutely no interest in freeing slaves. His main purpose was to maintain the union at all costs. “My paramount object in this struggle is to save the Union, and is not either to save or destroy slavery.”
Really you have no idea how Lincoln felt about slavery, nor how those feelings changed with time. His public statements are the carefully crafted words of a master politician.
For a guy with no interest in freeing slaves, he sure freed a lot of slaves.
"I cannot swallow whole the view of Lincoln as the Great Emancipator. As a law professor and civil rights lawyer and as an African American, I am fully aware of his limited views on race."
-- Someone who might know a little bit about being a politician
This is fun and all but it has nothing to do with my point.
Someone upthread provided a short list of African Americans who were murdered as a result of their notability.
In an attempt to refute the argument that to be a notable black in America is dangerous, Abraham Lincoln was introduced as an example of a notable white leader who was killed. There were any number of white leaders that could have been introduced as counterexamples, but, amusingly, the commenter chose one who was murdered because of white enmity towards blacks.
The question of whether Lincoln had any ambivalence about freeing slaves has little bearing on the question of why he was murdered. Had Lincoln not emancipated the slaves, he would not have been murdered. His death clearly belongs in the tally of "people killed because it's dangerous to be a successful black person in America".
"I am naturally anti-slavery. If slavery is not wrong, nothing is wrong. I can not remember when I did not so think, and feel. And yet I have never understood that the Presidency conferred upon me an unrestricted right to act officially upon this judgment and feeling."
He was very much against the expansion of slavery. This is clear in his writings and his voting record. I'm not saying that he was an outright racist, but take him in historical context. He resisted his party's call for emancipation for over two years into the Civil War, and he only issued the Proclamation once the North was all but sure to lose. And even then he only abolished it in states that were rebelling against the Union. He could never have abolished slavery outright given that there were six slave holding states that were fighting on his side that would have seceded immediately thereafter.
Lincoln repeatedly asserted that the President possessed no legal power to rewrite the United States Constitution. The only way he could justify emancipating the slaves was in his capacity as Commander in Chief of the armed forces, which meant that he had to wait until it became a military necessity.
He had already exercised his power as Commander in Chief by sending troops into combat. He didn't have to wait for it to become militarily necessarily -- the Constitution gives the President wide berth in this regard. It was reigned in with the War Powers Act in 1973. I'm not sure he was much of a strict Constitutional kinda guy either, as the Founding Fathers made allowances for states to secede, or reject the Union in whole. New York made sure they could back out of the federal government at any time before ratifying.