I accept that Booth's decision to murder Lincoln in otl was his own and that of his drinking buddies.
However I wonder if there were elements in the CSA administration, outraged by the emancipation proclamation and the recruitment of former slaves as soldiers who might have thought that killing the Union Commander in Chief was morally justified and politically smart.
How big a difference would it have made?
I am assuming that the traitor in chief, Jefferson Davis would not have been consulted on the grounds that he would say 'no'