I have read the Emancipation Proclamation and I've also read another document titled Constitution of the United States. And since the Constitution does not mention slavery then constitutionally Lincoln could not free the slaves in Union states and areas under Union control. Lincoln could free the slaves in the South because the Confiscation Acts, passed by Congress and upheld by the Supreme Court, allowed the government to seize private property without compensation if that property was being used to support the rebellion. So Lincoln could declare Southern slaves free so he issued the Emancipation Proclamation. It took the 13th Amendment to end slavery, which Lincoln got through Congress and on to the states for ratification. I'm surprised that you were unaware of all that.
While you are at it, why is a fact, and how can it be Constitutional to imprison the entire legislature of Maryland without trail, and lock them up (ironically) in Ft McHenry?
I would if it happened, but Chuck Baldwin crap to the contrary Lincoln never arrested the entire Maryland legislature. Authorities arrested some members of the legislature in September 1861 because they were advocating joining the Southern rebellion going on at the time and the authorities, not surprisingly, took a dim view of that. What do you think would have happened if in early 1942 members of the Texas legislature wanted to vote on joining the Axis side of the war?