Lincoln's entire political premise for the war revolved around evading responsibility for his.
Sure it was.
You kind of wonder why the whole fandango was started to 'preserve the Union' (presumably in formaldehyde, given the fact that they were willing to kill to preserve it), but then evolved into 'free the slaves down there (but not up here)'.
Triangulation! Pivot and adjust! A professional politician of the first rank...