The movie does not present the early parts of the war, in fact Lee and Grant are already facing each other at Petersburg, and Lincoln has won reelection, in the same election that swept many Democrats out of congress.
The passing of the thirteenth amendment was not easy as the movie portrays, and the movie shows the political moves, and promises Lincoln pulled out to official abolish slavery in the United States. Political victory would require 20 votes from across the aisle, while not losing any votes from the Republican Party.
The witticisms of Abraham Lincoln made for an enjoyable part of the movie, and I remember thinking during the movie, I wish I had written that down. Also his humorous stories kept the movie light, because the movie was heavy.
This movie was not a biography of Lincoln, nor was it a history of the civil war. It had very little of the actual action, other than some Africa Americans telling their story, and showing the result of battle. The Gettysburg Address is recited at the beginning of the move, and towards the end we see works from Lincoln's second inauguration.
The movie also does a very good job of portraying the son's of Mary and Abraham Lincoln. Robert, his oldest who wants to be in uniform rather than at school. He finally gets his wish, being placed on Grant's staff. Tad, his youngest is dealing with the death of the middle brother, Willie. He views lithographs of slaves, and is very much interested in the freedom of the slaves.
The other actors do a very good job. You would think a movie spending much of its time showing congress would be boring. In this case it was not, because the story took place in congress, and the manipulations, name calling, and in some cases restraining of one's opinions to get the amendment passed, were fascinating. Tommy Lee Jones as Representative Stephens from Ohio was terrific.
A very enjoyable movie.