No.
You explain to
me how it is the right of the Federal government to prevent states from seceding from a government which, according to its own founding document, exists pursuant to their "consent".
The ends do
not justify the means. Or, the only appropriate ends are determined by what lies within appropriate means. So, I don't give a damn what Lincoln's motivations were, and nor should you. "The road to hell is paved with good intentions." How you treat people is all that matters. And, if forcing people to work without their consent is wrong, then forcing people to obey a distant government without their consent is also wrong, albeit possibly to a lesser degree.
Those who are interested might read Lysdaner Spooner's
No Treason. Spooner was a prominent abolitionist (his
Unconstitutionality of Slavery was a great influence on Frederick Douglass's subsequent work) who, upon Southern secession, began making arguments very much like the one I've made here.
And he was a damn sight more persuasive than either of us.