The Jury system has a rather unusual interpretation in Murder on The Orient Express, at least by Western standards. A self-appointed group of twelve, the same number of people in a jury, convicts Ratchett to death and then murder him. The idea of a "jury" or the Justness of the jury becomes thematic material. The Jury is a symbol of Justness. The Armstrong family justified killing a many because they gathered twelve people together who through that Ratchett should die. However, their idea of a jury is nothing like the courtroom jury or jury as the state intended. They like Poirot, did not rely on any sort of law or otherwise to form their "jury." The "Jury" system is simply a consensus; it puts the responsibility of one man's death on the shoulders of many, rather than one. This is what the state does, the state assigns a jury who decides the fate of a man, but there is control over who is selected to be on the jury. If juries were made up of victims family members the jury would certainly be biased. However, we cannot know for sure that Ratchett did not commit the crime. The novel states that Ratchett, or Cassetti, "gave the law the slip," but he may not have been the man who murdered Daisy Armstrong.
The novel constantly questions what a jury is and how "just," this system of justice is, especially when a jury is self-appointed. The final argument of the novel, consistent with Poirot and all the characters is that Ratchett's murder was "just." The jury they formed, and the consensus of twelve, was right and fair.
From talks on Prohibition to murder laws in the United States, law is wholly insufficient in Murder on The Orient Express. Prohibition laws are discussed when Poirot searches Hardman's suitcase for evidence. His suitcase is lined with bottles of liquor and he tells the men that Prohibition hasn't ever "worried me any." Hardman and M. Bouc even discuss the speakeasy (the hidden, illegal bars during prohibition). Hardman is planning on concealing his alcohol by the time he gets to Paris, "what's left over of this little lot will go into a bottle labeled hairwash." Prohibition has not curbed the drinking habits of Hardman.
The insufficiency of US law is exemplified by the fact that Ratchett is able to give US cops, "the slip." By means of enormous wealth and the "secret hold he had over various persons" he was acquitted from the crime. After he was let free, Ratchett (formerly Cassetti) changed his name and went to travel on his money. The book suggests that a murderer in America can go free if he has enough money and connections.
Because Ratchett escapes justice in the United States, the Armstrong family is determined to kill him and prevent him from hurting any more children. One of the main themes of the novel is the morality of murder-is it all right to kill a man, even if law has acquitted him? Is it ever all right to kill a man? The novel suggests, at least by Poirot and the passenger's standards, that murder is Ok under the right circumstances. If the crime is hideous, there are twelve people who agree that a person is truly guilty and that person is still on the loose, and therefore it is fine to kill him. There are obvious emotional costs, most of the servants are in tears throughout the novel, but, overall, the Armstrongs are successful and probably will not receive punishment for their crime.
There is a strict class structure in most Christie's novels and especially in Murder on The Orient Express. Class not only represents one's financial well being, but emotional. The servants are much weaker characters than then the non working-class passengers. Hildegarde Schmidt, Greta Ohlsson, Antonio Foscanelli and, eventually Mary Debenham all break into tears by the novel's end. None of the other characters get so upset about the situation, perhaps because they do not have to. If they loose their jobs, it is not such a big deal, as they are independently wealthy and most are not required to work. Mary Debenham even tells Poirot she does not tell people she was associated with the Armstrongs because she is worried about securing other jobs. Although the cabin is made up of "many different classes and nationalities," it is strictly divided into working class and aristocratic passengers.
Americans, at least the two admitted, are comedic characters in the text. Both Hardman and Mrs. Hubbard use improper slang, are fairly obnoxious and think their country is the best, both caricatures of American males and females. Mrs. Hubbard prone to calling people "folks," tells people that Europe needs Western ideals and Hardman, who constantly speaks in awkward slang tells M. Bouc he would "learn a few go-ahead methods over there...Europe needs waking up. She's half asleep." Poirot agrees that America is a place of progress, but it is clear this progress isn't always positive.
One of the greatest motif is Murder on the Orient Express is that of identity. In the first two sections of the book, the passenger's identities are assumed to be correct, but in the third section the real identities of the passengers are revealed. The motif adds to the surprise of the book. As Poirot admits, there are no standard ways of investigating this case, so he and the reader are forced to first accept the evidence as the passengers as truth. There is no way to see if they are lying or not. Most of the passengers tell the truth about their names, but not their professions or association with the Armstrong family. Countess Andrenyi attempts to smudge and change her name, Heleana to Eleana, and Linda Arden makes up an entirely fictitious character to play while on board the train.
Ratchett becomes the symbol of pure evil in the novel. From the minute Poirot sees Ratchett in the hotel restaurant, he knows that he is a bad man. Poirot describes Ratchett as a "wild animal" and tells M. Bouc that when Ratchett passed "he could not rid himself of the evil that had passed me by very close." To the Armstrongs, Ratchett is evil as well. In the evidence gathering stage, when Poirot tells each of them about the crime and Ratchett's involvement, all of the passengers are outraged. The name Ratchett becomes synonymous with evil and terror. The close association of Ratchett and evil is purposeful, and Christie wants the reader to have no sympathy for this man.
Daisy Armstrong is symbolic of goodness and innocence. The three-year-old child, kidnapped and brutally murdered by an evil man for money, is the picture of purity. When each of the passengers speaks of the Armstrong case or specifically of Daisy, they can hardly contain their grief and anger that such a young, perfect life was taken. It is the duty of the Armstrong family to defend the good and murder evil, and it is their duty to defend Daisy and other young children like her by killing Ratchett.
Food is a symbol of society, sophistication and calm. M. Bouc, Dr. Constantine and Poirot always sit down at meals after every part of the investigation. Even after just having viewed Ratchett's dead, bloodied body, Constantine and Poirot go to the dining car and eat a full meal with M. Bouc. While eating his lunch, Poirot considers the case. When he is finished, he tells M. Bouc and Constantine that he knows Ratchett's true identity. Christie is careful never to leave out a meal, where and when Poirot is eating. In a time of great disorder and panic, food and the process of eating is ordered and sophisticated.