Abraham Lincoln emancipated the African Americans because?

Answer:
Because he had an urgent need to keep the British from intervening on the side of the Confederates.

If he officially turned the war into a crusade against slavery, the British could not intervene without looking pro-slavery in the eyes of the world. (The British had, of course, abolished slavery years earlier.)
First answer by Jonathan Begg. Last edit by Jonathan Begg. Contributor trust: 149 [recommend contributor recommended]. Question popularity: 1 [recommend question].