Not precisely a biopic, the film offers a fictionalized depiction of the early adulthood of the future U.S. President, a period extending from roughly 1832 to 1837. It follows Lincoln's career as a rural Illinois shopkeeper and aspiring politician, his decision to study law, and the beginnings of his law practice in Springfield, where a challenging murder case soon provides the inexperienced lawyer with a chance to make a name for himself.
Compare Abe Lincoln in Illinois, a 1940 film adapted from a 1938 stage play that tells basically the same story, and Steven Spielberg's 2012 film Lincoln, which was viewed by its screenwriter Tony Kushner as a Spiritual Successor to this film.
- Alcohol Hic: One of the jurors continually lets one out, being perpetually drunk on cheap alcohol.
- And Another Thing...: Lincoln pulls this on Cass just before he leaves the court, where he reveals his knowledge about the lunar pattern on the night of White's murder and correctly deduces that Cass was lying about his version of the events.
- Art Imitates Art: As Lincoln leaves the courthouse, there's a shot framed to look quite a bit like the pose of the Lincoln statue at the Lincoln Memorial.
- As the Good Book Says...: Lincoln quotes from the Sermon on the Mount in Matthew 5:7—"blessed are the merciful, for they shall obtain mercy"—when he is Shaming the Mob into leaving his clients alone.
- As You Know: Ann Rutledge telling Lincoln things he already knows about how he had almost no formal education.
- Asshole Victim: The man the Clay brothers are accused of killing, Scrub White, comes off as this. Whenever he's seen on screen, he's either harassing the wife of one of the Clay brothers or picking a fight with the Clay brothers.
- Blowing Smoke Rings: A completely relaxed Palmer Cass is doing this during the cross-examination scene, right before Lincoln drops the bomb on him.
- Call-Forward: Lincoln plays "Dixie" on a mouth organ, and his friend says that it "makes you want to march".
- Chekhov's Gun: The Clay family doesn't have any scratch paper for Lincoln to take notes on when they're interviewing him, so they give him an almanac to scribble on. This proves crucial to the climax, when Lincoln uses said almanac to prove that Cass is lying.
- Cool Old Guy: Judge Herbert A. Bell comes off as this. He frequently laughs at Lincoln's jokes and runs the courtroom impartially as the law demands. He even tries to help out Lincoln when the case starts going south for him, offering to appoint a more experienced attorney to aid Lincoln in his defense.
- Dances and Balls: Lincoln courts Mary Todd at a dance, dancing quite badly.
- Establishing Character Moment: Abe is playing a game of tug of war. He knows his team is losing so he hitches the rope to a wagon.
- The Ghost: Lincoln's law partner John Stuart is frequently mentioned by both Lincoln and Douglas, yet is never seen in the film. Lincoln mentions that he's out of town on some kind of business.
- He's Dead, Jim: Palmer Cass takes about five seconds to determine that Scrub White is dead. Justified at the end, when Cass confesses that he actually stabbed White himself.
- Law Procedural: The second half of the film basically functions as this, depicting as it does Lincoln's defense of the Clay brothers in their trial for Scrub White's murder.
- Obfuscating Stupidity: Nobody mistakes Lincoln for being stupid, but he certainly plays himself up as far more inexperienced and naive of the law than he actually is. This makes it all the more surprising to the court when he suddenly amps up his defense by using a sound logical argument against the prosecution's main witness.
- The Perry Mason Method: Palmer Cass has claimed that he saw one of the Clay brothers stab Scrub White. When asked how he could see that well from 100 yards away at 11 p.m., Cass said that it was "moon bright" that night. Lincoln whips out an almanac that shows that on the night in question the moon 1) was only in its first quarter, and 2) had already set anyway. He then accuses Cass of killing White himself. Cass breaks down and confesses.
- Reasonable Authority Figure: Sheriff Gil Billings goes out of his way to keep the Clay brothers safe from the lynch mob and treats them well while they're imprisoned in his office. Even if he does think they killed Scrub White, he doesn't antagonize them and continually protects them from the other lynch-happy townsfolk.
- Shaming the Mob: Lincoln does this to stop the lynch mob that is about to hang his prospective clients.
- Simple Country Lawyer: Lincoln leans on this hard in the trial, in contrast to his opponent, who is much more fastidious in his manner and dress.
- A Storm Is Coming: The American Civil War is coming, and it's alluded to here in the final shot, where a thunderstorm hits as Lincoln is walking away.
- Torches and Pitchforks: A torch-wielding mob almost lynches the two murder suspects, but Lincoln convinces them to go home.
- Unfortunate Names: J. Palmer Cass, according to Lincoln."If it's all the same to you, I'll call you Jack Cass."
- Very Loosely Based on a True Story: There really was a murder case in which Lincoln used an almanac, and pointed out what phase the moon was in, to discredit a witness. That case, the William Armstrong murder trial, took place in 1858, a good 20 years after this movie's time frame, when Lincoln was a nationally known political figure. (And the witness Lincoln discredited wasn't the murderer and didn't confess by The Perry Mason Method.)
- Worthy Opponent: At the end of the film, after Lincoln has won the case, Douglas admits that Lincoln has many talents and that he was wrong about his initial judgement of Lincoln's character. This is pretty significant, given the two's eventual intense political rivalry.
- Young Future Famous People: Not just Lincoln as an aspiring lawyer in his twenties, but also a young Stephen Douglas as both Lincoln's political rival and his rival for the hand of Mary Todd.