Agree. IMO, Lincoln put the critical stake in the ground by establishing that the Federal Government could do whatever it wanted. Revoke Habeus Corpus, etc.
What I have never understood is what was so all-fired important about keeping the US intact that was worth sacrificing the lives of a generation of young men on both sides and plunging the South into 100 years of penury? If it was about slavery (I agree the South seceded in large part over slavery) then where was the ultimatum: "Free your slaves by next Thursday or we are going to come kick your a**".?