Rick can't return to America because he killed someone to save Sam.It would explain both why Rick can't return to the States, and why Sam is running halfway around the world with him. Back in America, a white person (or group of people) tried to kill Sam, for whatever reason (a robbery, or a lynching, for example). Rick somehow got involved, and in the process of defending Sam, killed the attacker(s). Even though it was an act of defense, blame wound up on Rick and Sam, because it was the 1940s and the cops were racists. So Rick and Sam decided to escape to Europe, and later Casablanca. This theory would fit with what other characters say about Rick. More than once he's said to be someone who often winds up helping the "underdog." Louis speculates that Rick can't return to the States because he killed a man, and Rick confirms this; true, that conversation was sarcastic, but it may also have had some sincerity behind it.
Ugarte is a vampire.Look at him. Listen to that voice with that accent. It's obvious. He is an especially powerful vampire, since he is resistant to sunlight. Getting shot was a temporary setback. Consider that we never see Ugarte...
The entire film is a dream, in which Rick is incepted to join the cause against the Nazis.The events in “Casablanca” are all part of a dream that Rick has, while passed out in his bar after a night of boozing. Lazlo and his wife do arrive at Casablanca, but Rick does not see them in person; only when they entered his dream, with a team of inceptors trained to trick Rick into subconsciously deciding to resist the Nazis. The team members include Lazlo, Ilsa, Louis, and an unseen fourth member. Their plan is to set up a chain of events that will cause Rick to feel guilt about not helping foreigners pursued by Nazis, force him to finally turn against the Nazis and “help” someone, and give him a sense of catharsis about the whole thing (because positive emotion trumps negative). First, the unseen fourth team member takes care of the guilt part; he or she is able to change his or her appearance while inside someone’s dream (like Eames). He/she appears first as Ugarte, begging Rick for help before getting “killed,” to solidify a sense of guilt in Rick’s subconsiousness. Then, Lazlo and Ilsa step in. Lazlo tries to convince Rick to “help” him and his wife by appealing to Rick’s noble side, while Isla appeals to his emotion. She tells him about her secret marriage to Lazlo, so that Rick will come to stop blaming her, and feel a catharsis about letting her go. This is crucial in freeing Rick of his bitterness against the world, and so he can stop being self-serving. The fourth team member, meanwhile, returns to Rick’s café in the form of different desperate foreigners (like the Bulgerian woman trying to help her husband) to continue feeding Rick guilt and test whether his actions will change. Louis, meanwhile play thse devil’s advocate. In order to change Rick’s mind about his part in the war, the group needs something to test him against. Louis acts obedient to the Nazis, like Rick, to make Rick question his own actions (or lack of) concerning the war. Major Strasser was merely a projection of Rick’s dream, representing his fear of the Nazis and the control they have over his mind. When Rick shoots Strasser at the end, he subconsciously “kills” the control the Nazis have put over him with fear. Letting Ilsa go with her husband on the airplane is Rick’s official catharsis, accepting that he cannot have her, and doesn’t need to, because others’ needs are more important than his own desires. Rick will soon wake up after this, because he has now donned his fedora…his totem. He wore it in his other dreams (like the dream where he was a detective searching for the Maltese Falcon). He hasn’t been wearing it for most of this dream, because he chose to forget that he was dreaming. But now that his totem is with him, he will soon be reminded to wake up. And when he does, he will have a new sudden urge to join the Allies against the Nazis.
This film takes place in the same universe as The Maltese Falcon.Joel Cairo? Casper Gutman? Do these sound like names a person would likely be born with, or more like meaninglful aliases that criminals might pick for themselves? Even Sam Spade sounds a bit too cool to be real; it may well have just been the detective's professional name (like a pen name or a stage name). At the end of The Maltese Falcon, Cairo and Gutman were supposedly arrested, but we didn't see it. That's because they escaped, and a few years later wound up in Casablanca, pretending to be Italians with the new names of Ugarte and Ferarri. (They didn't bother disguising their Hungarian and British accents, since no one asks questions in Casablanca). Sam wound up having to leave America for his own reasons, and once in Europe, started to go by Rick Blaine (possibly his real name all along). Rick has dealt with Ferrari and Ugarte in the past. The events of The Maltese Falcon job are that backstory.
Ugarte was involved with the Italian Mafia.Ugarte is an Italian name, and many sources say the character is meant to be Italian (Peter Lorre's Hungarian accent notwithstanding). The Mafia absolutely hated the Nazis, which would explain why Ugarte had no moral problems at all with killing the two Nazi couriers. His confusion when Rick is disgusted with his murders, rather than impressed by them, makes sense if Ugarte was born and raised in a world of organized crime, where killing someone might be considered a triumph.