Klaatu: I am leaving soon, and you will forgive me if I speak bluntly. The universe grows smaller every day, and the threat of aggression by any group, anywhere, can no longer be tolerated. There must be security for all, or no one is secure. Now, this does not mean giving up any freedom, except the freedom to act irresponsibly. Your ancestors knew this when they made laws to govern themselves and hired policemen to enforce them. We, of the other planets, have long accepted this principle. We have an organization for the mutual protection of all planets and for the complete elimination of aggression. The test of any such higher authority is, of course, the police force that supports it. For our policemen, we created a race of robots. Their function is to patrol the planets in spaceships like this one and preserve the peace. In matters of aggression, we have given them absolute power over us. This power cannot be revoked. At the first sign of violence, they act automatically against the aggressor. The penalty for provoking their action is too terrible to risk. The result is, we live in peace, without arms or armies, secure in the knowledge that we are free from aggression and war. Free to pursue more... profitable enterprises. Now, we do not pretend to have achieved perfection, but we do have a system, and it works. I came here to give you these facts. It is no concern of ours how you run your own planet, but if you threaten to extend your violence, this Earth of yours will be reduced to a burned-out cinder. Your choice is simple: join us and live in peace, or pursue your present course and face obliteration. We shall be waiting for your answer. The decision rests with you.
Army physician: [about Klaatu] He was very nice about it, but he made me feel like a third-class witch doctor.
George Barley: Why doesn't the government do something, that's what I'd like to know.
Mr. Krull: What can they do, they're only people just like us.
George Barley: People my foot, they're democrats.
Mrs. Crockett: You're a long way from home, aren't you, Mr. Carpenter?
Klaatu: How did you know?
Mrs. Crockett: Oh, I can tell a New England accent a mile away.
Klaatu: I'm worried about Gort. I'm afraid of what he might do if anything should happen to me.
Helen: Gort? But he's a robot. Without you, what could he do?
Klaatu: There's no limit to what he could do. He could destroy the Earth.
Mr. Harley: Your impatience is quite understandable.
Klaatu: I'm impatient with stupidity. My people have learned to live without it.
Mr. Harley: I'm afraid my people haven't. I'm very sorry... I wish it were otherwise.
Klaatu: I won't resort to threats, Mr. Harley. I merely tell you the future of your planet is at stake.
Barnhardt: Have you tested this theory?
Klaatu: I find it works well enough to get me from one planet to another.
Helen: What about the rest of the world?
Tom: I don't care about the rest of the world!
[Seeing her shocked expression]
Tom: You'll feel different when you read about me in the papers.
Helen: I feel different now.
Barnhardt: Tell me, Hilda, does all this frighten you? Does it make you feel insecure?
Hilda: Yes, sir, it certainly does.
Barnhardt: That's good, Hilda. I'm glad.
Klaatu: You have faith, Professor Barnhardt?
Barnhardt: It isn't faith that makes good science, Mr. Klaatu, it's curiosity. Sit down, please. There are several thousand questions I'd like to ask you.
Barnhardt: One thing, Mr. Klaatu: suppose this group should reject your proposals. What is the alternative?
Klaatu: I'm afraid there is no alternative. In such a case, the planet Earth would have to be... eliminated
Barnhardt: Such power exists?
Klaatu: I assure you, such power exists.
Klaatu: I am fearful when I see people substituting fear for reason.
Bit Man: They're here! They're here! They've landed! Over on the mall! They've landed!
Bobby Benson: Department of Commerce. She's a secretary. They have a man they call the Secretary, but he isn't at all. My mother's a *real* secretary.
Bobby Benson: [indicating grave marker during a visit to Arlington] That's my father. He was killed at Anzio.
Klaatu: Did all those people die in wars?
Bobby Benson: Most of 'em. Didn't you ever hear of the Arlington Cemetery?
Klaatu: No, I'm afraid not.
Bobby Benson: You don't seem to know much about anything, do you, Mr. Carpenter?
Klaatu: Well, I'll tell you, Bobby, I've been away a long time. Very far away.
Bobby Benson: Is it different where you've been? Don't they have places like this?
Klaatu: Well, they have cemeteries, but not like this one. You see, they don't have any wars.
Bobby Benson: Gee, that's a good idea.
Bobby Benson: [to Klaatu] I like you Mr. Carpenter, you're a real screwball!
American Radar Operator: Holy Mackerel! Call headquarters. Get the lieutenant.
Klaatu: [after reading the Gettysburg Address at the Lincoln Memorial] Those are great words.
Klaatu: [turns to look at the statue of Lincoln] He must have been a great man.
Bobby Benson: Well sure.
Klaatu: [walking out of the memorial, then turning to look at Lincoln again] That's the kind of man I would like to talk to.
[Klaatu is revived by Gort after being fatally shot]
Helen: I - I thought you were...
Klaatu: I was.
Helen: You mean... he has the power of life and death?
Klaatu: No. That power is reserved to the Almighty Spirit. This technique, in some cases, can restore life for a limited period.
Helen: But... how long?
Klaatu: You mean how long will I live? That no one can tell.
Reporter: I suppose you are just as scared as the rest of us.
Klaatu: In a different way, perhaps. I am fearful when I see people substituting fear for reason.
Klaatu: Perhaps before deciding on a course of action, you'd want to know more about the people here - to orient yourself in a strange environment.
Mrs. Barley: There's nothing strange about Washington, Mr. Carpenter.
Klaatu: A person from another planet might disagree with you.
Mrs. Barley: If you want my opinion, he came from right here on Earth. And you know where I mean.
Mr. Krull: They woudn't come in spaceships, they'd come in airplanes.
Mrs. Barley: I woudn't be too sure about that.
Secretary: The phone doesn't work.
Mr. Krull: Well then call the phone company.
Secretary: But... the phone doesn't work!
Army physician: I don't know whether to get drunk or quit the practice of medicine.
Helen: Now, you didn't really see a spaceship, but you thought you did.
Bobby Benson: I'd never call YOU a liar.