when lincoln freed the slaves he had no control over the south, they were not part of the north, when the south re-joined the north as part of the united states they had to let their slaves free because they were joining a nation where slavery was illegal (every state in the north had made slavery illegal or abandoned slavery without making it officially illegal before lincoln did anything and the south went its own way). he also suspended the writ of habeas corpus, and he was the only president to do so (although recent presidents have done the same action but without suspending it because they were detaining prisioners on non-us soil) which is why imo, lincoln was not a good president.