No that took the 13th Amendment, as I'm sure you know. He was able to free the slaves in those areas in rebellion as a war measure. The government was allowed to seize without compensation any property of any citizen that was used to support the rebellion. That included slaves.
And what part of the constitution gives the government the authority to do that. Silly me, I thought they had a "due process" requirement to seize any property.
Fifth amendment, if you want to look it up.
Of course I anticipate you are going to say "Insurrection"! Or "Rebellion"! by way of justification, but the problem with this idea is two fold.
Firstly it wasn't a rebellion or an insurrection.
Secondly, you can't merely declare everyone living in a certain area as "rebels" and deny them civil rights without going through "due process." There were a lot of people who were not supportive of the confederacy but who happened to be living in territory the confederacy controlled.
Declaring them all "rebels" and "Insurrectionists!" (Like they are doing now with people at the January 6th rally in Washington DC.) is not allowed under constitutional law.
It's like declaring someone a "criminal" and then punishing him without trial.
An honest person would have to face the fact that they went way beyond their legal authority in doing the things they did, but of course I don't expect you to acknowledge this.