Legally? The individuals in those states were.
Morally? That's a much more nebulous situation where Lincoln could be equally culpable. Then again, there is the golden rule: he who has the gold makes the rules.
I don't claim to be anything more than a (below?) average constitutional scholar. And that's why I prefaced my answer with "If I'm understanding correctly" types of rejoinders. I'm definitely open for discussion on it...