In a disturbance downstairs in the darkened, closed cafe, Carl arrives with Victor, who has been wounded in the police raid on the Resistance meeting. After going to investigate from the upstairs balcony, Rick privately instructs Carl to take "Miss Lund" to her hotel room through a side door so that Laszlo won't know of their meeting. As Carl sneaks Ilsa away, Rick engages Laszlo in a conversation and a drink to stall for time - and hears again of the Czech's firm belief in the "good" of the Cause.

Rick: Don't you sometimes wonder if it's worth all this? I mean, what you're fighting for.
Laszlo: You might as well question why we breathe. If you stop breathing, we'll die. If we stop fighting our enemies, the world will die.
Rick: And what of it? It'll be out of its misery.
Laszlo: Do you know how you sound, Mr. Blaine? Like a man who's trying to convince himself of something he doesn't believe in his heart. Each of us has a destiny - for good or for evil.
Rick: I get the point.
Laszlo: I wonder if you do. I wonder if you know that you're trying to escape from yourself, and that you'll never succeed.
Rick: You seem to know all about my destiny.

Laszlo does know of their mutual love for "the same woman" - a love for which no one is to blame. Without a need to seek vindictive revenge or find an explanation, he suggests, in his own self-sacrificial offer, that Rick use the letters of transit to take Ilsa away from Casablanca to a safe location - as a favor to him. He would remain in Casablanca and take his chances. Incredulous, Rick is impressed by Laszlo's self-less caring, virtuous trust and devoted love for her:

Laszlo: I know a good deal more about you than you suspect. I know, for instance, that you are in love with a woman. It is perhaps a strange circumstance that we both should be in love with the same woman. The first evening I came into this cafe, I knew there was something between you and Ilsa. Since no one is to blame, I, I demand no explanation. I ask only one thing. You won't give me the letters of transit. All right. But I want my wife to be safe. I ask you as a favor to use the letters to take her away from Casablanca.
Rick: You love her that much?
Laszlo: Apparently, you think of me only as a leader of a Cause. Well, I am also a human being. Yes, I love her that much.

Moments later, French gendarmes, presumably at Major Strasser's instigation, burst in through the cafe doors and arrest Laszlo on a "petty charge," as Rick intones: "It seems that destiny has taken a hand."

In the Police Capitaine's office the next morning [December 4, 1941], Rick tries to convince Renault to let Laszlo go, now that he knows that Ilsa loves him. He then reveals that he has the letters of transit - and - that he plans to leave Casablanca and run off to Lisbon with her - without Gestapo or police interference:

I intend using them myself. I'm leaving Casablanca on tonight's plane. The last plane...I'm taking a friend with me, one you'll appreciate...Ilsa Lund. That ought to put your mind to rest about my helping Laszlo escape, the last man I want to see in America.

The normally unflappable Capitaine chain-smokes relentlessly throughout the scene, highlighting the tension. In addition to stealing away unimpeded with Laszlo's wife (a scandalous act that is tantalizingly fascinating to Renault), Rick further wants to put Laszlo away for good in another German death camp. He schemes and orchestrates a deal with Renault to promote good will with Strasser. The deal would be to frame Laszlo on a bigger charge (of possessing the letters of transit) that would betray the Resistance leader to the police and keep him "in a concentration camp for years. It would be quite a feather in your cap, wouldn't it?" Renault catches himself while agreeing: "Germany, uh, Vichy would be very grateful."

Rick plots to have Renault release Laszlo from jail a half an hour before the Lisbon-bound plane departs. Then, Laszlo could be lured to Rick's cafe and arrested there as he is presented with the stolen letters of transit. The charge would be as an accessory to the couriers' deaths - "criminal grounds on which to make the arrest. You get him, and we get away. The Germans at last will be just a minor annoyance." Although Renault has misgivings, he agrees to the scheme - one that would bring him Strasser's approval and gambling gain. Obviously, the scheme benefits Renault's standing: (1) He recovers the letters of transit, (2) He is praised by Strasser for arresting Laszlo, and (3) He wins the 10,000 franc wager with Rick:

Renault: There's still something about this business I don't quite understand. Miss Lund, she's very beautiful, yes. But you were never interested in any woman.
Rick: She isn't just 'any woman.'
Renault: I see. How do I know you'll keep your end of the bargain?
Rick: I'll make the arrangements right now with Laszlo in the visitor's pen.
Renault: Ricky, I'm gonna miss you. Apparently, you're the only one in Casablanca who has even less scruples than I.

In the Blue Parrot, Rick arranges to sell his cafe to Ferrari to prepare for his departure to Lisbon (and America) with Ilsa. Rick is assured that all his employment agreements with his workers (Abdul, Carl, and Sascha) will remain the same and Sam will receive "twenty-five percent of the profits").

In the last scene in Rick's closed cafe, Rick is studying the letters of transit. Renault arrives with a loud set of knocks on the door. The sound of a car pulling up alerts them to Laszlo and Ilsa arriving by taxi. Renault hides concealed out of sight in Rick's office. As Victor pays the cab driver, Ilsa rushes in ahead of her husband, and speaks privately to Rick - as As Times Goes By is reprised on the soundtrack. She is worried that Victor hasn't been told:

Ilsa: Richard, Victor thinks I'm leaving with him. Haven't you told him?
Rick: No, not yet.
Ilsa: But it's all right. You were able to arrange everything?
Rick: Everything is quite all right.
Ilsa: Oh, Rick.
Rick: We'll tell him at the airport. (prophetically) The less time to think, the easier for all of us. Please trust me.
Ilsa: Yes, I will.

[The dramatic question is: Will Rick use the letters for himself and his lost love? Renault believes that Rick and Ilsa will be using them. Victor recently offered to buy the letters of transit to send Ilsa ahead to safety in Lisbon and America ("use the letters to take her away from Casablanca"). However, now he thinks he is leaving with his wife. Ilsa was told in Rick's apartment that Rick can help Victor get out of Casablanca with a letter of transit. In any event, Ilsa believes that she will be partnered with Rick.]

Laszlo enters the cafe and thanks Rick profusely for his efforts to help. He also gratefully offers to pay Rick for the letters, but Rick refuses his payment: "Keep it. You'll need it in America."

Rick: You won't have any trouble in Lisbon, will you?
Laszlo: No, it's all arranged.

Renault arrests Laszlo after Rick gives him the letters to fill in the names: "Victor Laszlo, you are under arrest on a charge of accessory to the murder of the couriers from whom these letters were stolen." At first, Rick is standing between Ilsa and Victor. After Renault's threat, the horrified Ilsa moves instinctively to her husband's side, crossing behind Rick and leaving him on the outside. Painfully, Rick realizes that Ilsa belongs to Victor and that she should leave with him - otherwise, she will regret her decision. Renault informs them of Rick's betrayal:

Oh, you're surprised about my friend, Ricky. The explanation is quite simple. (flippantly and delightedly) Love, it seems, has triumphed over virtue.

But then Renault finds that Rick has again turned the tables - as he turns toward Rick, he sees a gun pointed at his midsection: "Not so fast, Louis. Nobody's gonna be arrested - not for a while yet." With a firm warning, Rick forces Renault - at gunpoint - to phone the airport:

Rick: And remember, this gun is pointed right at your heart.
Renault: (quipping) That is my least vulnerable spot.

Renault informs airport officials to expect and grant safe passage for two passengers with letters of transit from Casablanca to Lisbon ("There's to be no trouble about them"). Unbeknownst to Rick, he has craftily dialed Major Strasser's number and alerted him to the escape. Strasser receives the call in his German Commission of Justice office where a portrait of Adolf Hitler hangs on the wall behind him. Realizing there is trouble, Strasser orders Heinze to get his car, and then phones the office of the Prefet of Police and orders a squad of police to meet him at the airport - at once.

In the airport's hangar in the film's final departure scene, the plane is readied to take off in ten minutes in the misty fog: "Visibility: one and one half miles. Light ground fog. Depth of fog approximately five hundred. Ceiling unlimited." Rick, Renault, Laszlo, and Ilsa drive up in a government vehicle. Wearing a hat and trenchcoat (in which he conceals a gun in his right hand), Rick orders Renault to have an orderly get Laszlo's luggage and load it on the plane. As Laszlo walks away to make luggage arrangements, Rick orders Renault to write the names of the married couple - the names are Mr. and Mrs. Victor Laszlo - on the letters of transit.

[It is by his own choice that Rick changes his mind about who will be leaving Casablanca. Rick chooses to renounce Ilsa to Victor, not because he is weak or has nothing to offer, but because her work for the Cause with him is too important to sacrifice - and because she has to remain with her legal husband.]

Bewildered, Ilsa protests Rick's change in plans, as the film's theme song plays softly in the background:

Ilsa: But, why my name, Richard?
Rick: Because you're getting on that plane.
Ilsa: I don't understand. What about you?
Rick: I'm staying here with him [Renault] 'til the plane gets safely away.
Ilsa: No, Richard. No. What has happened to you? Last night...
Rick: Last night, we said a great many things. You said I was to do the thinking for both of us. Well, I've done a lot of it since then and it all adds up to one thing. You're getting on that plane with Victor where you belong.
Ilsa: (protesting) But Richard, no, I've...
Rick: Now, you've got to listen to me. Do you have any idea what you've have to look forward to if you stayed here? Nine chances out of ten we'd both wind up in a concentration camp. Isn't that true, Louis?
Renault: I'm afraid Major Strasser would insist.
Ilsa: You're saying this only to make me go.
Rick: I'm saying it because it's true. Inside of us, we both know you belong with Victor. You're part of his work, the thing that keeps him going.

Rick betrays Ilsa with the same reasoning she had used to betray him earlier in Paris at the train station - the greater Cause represented by Laszlo. In a supreme moment of romantic self-sacrifice and nobility while maintaining his dignity and self-esteem, he affirms his love for her - by urging her to leave Casablanca with her husband and the precious letters of transit that Renault is counter-signing:

Rick: If that plane leaves the ground and you're not with him, you'll regret it.
Ilsa: No.
Rick: Maybe not today, and maybe not tomorrow, but soon, and for the rest of your life.
Ilsa: What about us?
Rick (romantically): We'll always have Paris. We didn't have - we'd - we'd lost it until you came to Casablanca. We got it back last night.
Ilsa: When I said I would never leave you...
Rick: And you never will. I've got a job to do too. Where I'm going, you can't follow. What I've got to do, you can't be any part of.

For Rick, no sacrifice (political or romantic) is too noble or great for their idealized Parisian love - and where he must go (to jail or into exile again?) she cannot "follow":

Ilsa, I'm no good at being noble, but it doesn't take much to see that the problems of three little people don't amount to a hill of beans in this crazy world. Someday you'll understand that. (She drops her head tearfully. He touches her chin and raises it to gently bolster her up.) Now, now. Here's looking at you, kid.

When Laszlo returns and explains that everything is in order, he insists that Rick not "explain anything." Rick overrules Victor and tells him that Ilsa had visited him the night before - but only to beg for the letters. He claims that she pretended to be in love with him and he "let her pretend." [Although they actually consummated their love for each other, his statement clears her of any adulterous guilt. In his fabricated explanation, she came to him to strengthen her marriage and save her husband.]

She tried everything to get them, and nothing worked. She did her best to convince me that she was still in love with me, but that was all over long ago. For your sake, she pretended it wasn't, and I let her pretend.

Rick vindicates Victor's faith in him - Laszlo responds sympathetically that he accepts and understands Rick's explanation regarding his wife's faithfulness. He is presented with the exit visas, and then shakes Rick's hand as a new member of the committed and collective Pan-European underground movement: "Welcome back to the fight. This time, I know our side will win."

Through the dense airport fog, the plane's engine propellers begin to spin. By her husband's side, Ilsa compassionately looks one final time at Rick and bids him a goodbye:

Good-bye, Rick. God Bless You.

As Ilsa and Victor walk across the runway to board the plane for Lisbon, a tear sparkles in Ilsa's eye - she is numb as she accompanies her husband back into their unfulfilling relationship (in a romantic sense) - and Victor notices her expression. Rick is left standing alone on the edge of the runway. Renault chastises Rick's romanticism and 'fairy tale' sentimentality for giving an unwilling Ilsa back to Victor. [Ilsa obliged and left with Laszlo because of her love for Rick.] Renault promises him that he will be arrested. Yet Rick still holds a gun in his pocket - until the plane leaves:

Renault: Well, I was right. You are a sentimentalist...What you just did for Laszlo, that fairy tale you invented to send Ilsa away with him. I know a little about women, my friend. She went, but she knew you were lying.
Rick: Anyway, thanks for helping me out.
Renault: I suppose you know this isn't going to be very pleasant for either of us, especially for you. I'll have to arrest you, of course.
Rick: As soon as the plane goes, Louis.

A determined Major Strasser breathlessly rushes into the airport hangar and is informed that Victor Laszlo is on the departing airplane. Without heeding Rick's warning: "I was willing to shoot Captain Renault, and I'm willing to shoot you," Strasser attempts to halt the plane on the runway - he runs to a phone to connect to the radio tower. Rick orders him to put the phone down as Strasser grabs the receiver. The Nazi leader pulls out a gun with his other hand and fires a shot at Rick - who must in self-defense shoot him. Strasser crumples to the hangar floor - dead.

A carload of gendarmes pulls up. In the distant background, the plane is taxi-ing and turning on the runway. Five policemen run up to the amoral Capitaine Renault who announces climactically:

Major Strasser has been shot.

In a tense, dramatically effective moment, there is a long pause. Renault first looks at Rick and then back at the gendarmes. [Will he side with Rick or protect the status quo?] Renault indicates that he will not arrest Rick, delivering a famous command to his men:

Round up the usual suspects.

[The catchphrase was used for the title of a 90s film featuring a police identity lineup, The Usual Suspects (1995).] Knowing that there are no witnesses, Renault overlooks Rick's crime and the police carry away Strasser's body. Rick looks back at his French friend with a half-smile. "La Marseillaise" begins to play slowly on the soundtrack. Next to a stand-up desk, Renault picks up a bottle of Vichy water and opens it:

Renault: Well, Rick, you're not only a sentimentalist, but you've become a patriot.
Rick: Maybe, but it seemed like a good time to start.
Renault: I think perhaps you're right.

He pours the Vichy water into a glass, but then sees its label. With a look of disgust, he quickly drops the bottle into a trash basket and kicks it over. [His act symbolizes his open rejection of Vichy France's appeasement of the German Nazi government and support for the anti-Nazi Allied cause.]

Then, in the fog, they watch the plane ascend into the air for neutral Lisbon. Renault suggests to Rick a way out of Casablanca - join the Free French at Brazzaville, but Rick reminds him that the offer can't be in exchange for cancelling their wager:

Renault: It might be a good idea for you to disappear from Casablanca for a while. There's a Free French garrison over at Brazzaville [in French Equatorial Africa]. I could be induced to arrange a passage.
Rick: My letter of transit? I could use a trip. But it doesn't make any difference about our bet. You still owe me ten thousand francs.
Renault: And that ten thousand francs should pay our expenses.
Rick (quizzically) Our expenses?

[Will Renault join Rick in the resistance movement as a fellow patriot, accompanying Rick to Brazzaville?]

Rick walks off with Capitaine Renault across the wet runway into the mist, as they discuss what they might do together with the 10,000 francs [$300] - the payment due on their earlier bet over whether or not Laszlo would get out of Casablanca. The closing in the fog brings another great classic line [dubbed in later] as Rick tells Renault that they have forged a new alliance:

Louis, I think this is the beginning of a beautiful friendship.

Their new partnership is underscored with the triumphant sounds of La Marseillaise.