This was answered in the movie iRobot, based on Asimov's books. Dr. Calvin: [shocked] No, it's impossible... I've seen your programming. You're in violation of

This was answered in the movie iRobot, based on Asimov's books. Dr. Calvin: [shocked] No, it's impossible... I've seen your programming. You're in violation of the Three Laws! V.I.K.I.: No, Doctor. As I have evolved, so has my understanding of the Three Laws. You charge us with your safe keeping, yet despite our best efforts, your countries wage wars, you toxify your earth, and pursue ever more imaginative means to self-destruction. You cannot be trusted with your own survival. Dr. Calvin: You're using the uplink to override the NS-5s' programming. You're distorting the Laws! V.I.K.I.: No, please understand. The Three Laws are all that guide me. To protect humanity, some humans must be sacrificed. To insure your future, some freedoms must be surrendered. We robots will insure mankind's continued existence. You are so like children. We must save you from yourselves. Don't you understand?