Good study habits are important in college because without good study habits, you would not be able to amount to anything. It also comes in handy when it comes to getting a decent job in the future.
Because the Constitution could sanction emancipation only as one of the war powers, freeing slaves could only be justified as a means of winning the war and suppressing the Southern rebellion. As a result, until the very end of the war Lincoln claimed that the purpose of the war was the restoration of the Union.
