Factual error: Raymond is equipped with what is described as a high-power Soviet sniper rifle. However, the rifle he uses is actually a Japanese carbine.
Factual error: The movie is set in the mid 1950s, as established by the cars and 48-star American flag cake seen at the party scene. However, the convention hall at Madison Square Garden has 50-star American flags hanging from the ceiling.
Factual error: In the scene when the Senator and Raymond's mother are in the hotel room, the newspaper headline (upside down in the lower right) states that he will address the Senate that day. However, in the next scene when he proclaims there are 57 Communists (based on the Heinz ketchup), there is an uproar in the chamber and he yells "Point of order, Mr. Speaker." The Speaker (of the House) is not in the Senate, he is the head of the House of Representatives.