hehehhe time for my civil war obsession to come in handy
Lincoln needed to announce it right after a big win for the Union. Antietam happened to be a well timed one.
Doing it after a big victory would help reinforce the fact that he was doing the right thing in the war, and that he was a good leader (good enough to be re-elected).
Announcing it right after a loss would be viewed as a weak, desperate move, and Lincoln couldn't afford that if he was to be running again for president.
Answer:
The purpose of the Preamble is to state why the Declaration Of Independence was written. The document explains the reasons that impel the colonists to separate from Great Britain. The Declaration Of Natural Rights declares that all men are created equal. ... The role of their government was to protect the people's rights.
