Continuity mistake: In the final dinner meeting of the Merchants of Death (MOD Squad),the gun lobbyist gets a piece of pie with cheese on it, takes a small bite; then the alcohol lobbyist attacks it with her fork for a bite, pulling all the cheese off and toppling the little American flag in it. In the next shot of Bobby eating, and a closeup of the dessert, all the cheese is back on it and the flag is upright again.
Continuity mistake: During the Subcommittee Hearing scene, the person sitting behind Nick Naylor, on his left, changes repeatedly between shots: Right before he is asked to come forward, the chair is occupied by a woman in a blue shirt. When he sits down, a man is seated there. Immediately after one of the senators asks, "What about the children?", the woman is back - but only for a few seconds.
Factual error: After Nick Naylor visits "The Captain" in Winston-Salem, North Carolina, he is being driven to the airport to fly back to Washington. In one shot, mountains are visible in the background. However, they are brown and barren, like mountains in Southern California, which is probably where that scene was shot. How come many movie and television directors don't seem to understand that mountains in the Eastern U.S. look different from mountains in the West?
Continuity mistake: When Aaron Ekhardt returns from meeting with Robert Duvall, he meets with his boss JK Simmons. Simmons is wearing reading glasses when we first see him. A shot behind him also reveals this. They are removed at a shot of him from behind Ekhardt, then in another shot behind Simmons, they're still on. From the rest of the shots on, his glasses remain off.
Continuity mistake: When the main character goes to pay off the Marlboro man, he grabs his briefcase from the back seat and sits it on his lap. He says something to his son then reaches for the door handle. The camera position changes to an outside angle, looking into the car. At this time, the main character again reaches in the back seat to grab the briefcase.
Continuity mistake: When Nick is home after being fired and binging on takeaway food, his son and Jill come over. He is unshaven when he walks to the door, but when he sits down to talk to his son he is clean shaven.
Factual error: In an early scene with the lobbyist's family having dinner, they're eating take-out chicken from Dinah's, you can tell from the bucket featured. Dinah's is a California only restaurant but they don't live there - you know this because a short time later, the lobbyist-father and his son exclaim, "We're going to California."
Character mistake: Nick and the film director talk about cigarettes blowing up in the all-oxygen environment of a space station. Spacecraft don't have an all-oxygen environment- this would kill the astronauts inside it. Oxygen exhibits toxic effects above a certain partial pressure under most circumstances.
Continuity mistake: When Nick meets Heather for the first time, she is wearing a pink blazer. As the waiter pours the wine, her jacket abruptly disappears. (00:28:05)
Revealing mistake: In the shots of the Washington Probe office, when Heather sees Nick talking to the press about his affair with her, the newspaper staff are working on computers that (except for one) have no cables connected to them. (01:14:35)