Watched the film last night; quite good but not near classic (but not because of too much politics). Day-Lewis was great and Field and Jones very good (especially since better than I expected). I didn't recognize Spader (but occasionally found his character annoying).
Frederick Douglass could and should have played a role. Having read the book, Mary directly telling Stevens Lincoln will always be more popular than him and Abraham trying to discourage his son from enlisting (especially to the extent he did) weren't included and here felt inauthentic.
I think the Constitution was ambiguous on the legality of secession and while the South initiated combat, drafting people into combat was immoral (and here certainly glossed over).