A mock dialog to illustrate one of the [many] plot holes in Dune:
Piter: "But we have an agent within the Atreides household, one that will bring us victory!"
Feyd-Ruatha: "Indeed? Such an agent will surely be detected by the brilliant minds of House Atreides!"
Piter: "They shall ignore the agent - for it is Doctor Yueh!"
Feyd-Ruatha: "But he has Imperial Conditioning from the Suk School! The highest level of moral and psychological training and conditioning known to mankind! They are mentally, morally, and psychologically incapable of taking a human life, of betraying their employers in any way; in centuries of effort no one has EVER broken Imperial Conditioning! Even the Emperor himself trusts Suk doctors! If you have truly found a way to break this conditioning, why! it would shake the very foundations of psychology, medicine, and even politics!"
Piter: "Indeed, that is why we must carefully shift the blame for betrayal to another and then kill Dr. Yueh as soon as he is finished. If the Emperor were to know we had broken Imperial Conditioning he would destroy our entire House!"
Feyd-Ruatha: "But. I must know how you succeeded in breaking the unbreakable; how you thwarted training that 10 generations of effort found unthwartable; how you gained a tool that could be used to kill the Emperor himself. You must tell me!"
Piter: "I will tell you. We.... We.... We... threatened his wife! BWA-HA-HA-HA-HAAAAAAAA!"
Piter: "We, uh, threatened his wife."
Feyd-Ruatha: "OK. And...?"
Piter: "What do you mean, 'and'? We kidnapped his wife, roughed her up a bit, and threatened to kill her if he didn't do as we told him."
Feyd-Ruatha: "But, but, but - that's, like, Street Thug 205; 'to make a guy do what you want, threaten a loved one'. It is so common that it is a cliche. You're telling me that you broke the highest level of mental, emotional, ethical, and psychological conditioning known to Man by saying 'be a shame if something happened to your wife'?"
Piter: "But he really loves his wife! I mean, he'd be really sad if she were to die, so..."
Feyd-Ruatha: "Listen, you dime-store Eddorian, of course he loves his wife - people love their spouses, THAT'S WHY THEY GET MARRIED! Face it, this is obviously a ruse and Dr. Yueh is working with House Atreides."
Piter: "What?! No, I have carefully subverted Imp..."
Feyd-Ruatha: "Knock it off. There are well-documented cases in history of people with no conditioning other than a strong moral code allowing hostages, including their own loved ones, to be harmed rather than act in an immoral manner or betray their overlords. There is no way Imperial Conditioning would leave Suk doctors vulnerable to the favorite tactic of heavies in a two-reel Gene Autry serial, You're being played, you dope!"
Piter: But as a Mentat I have broken Imperial Cond..."
Feyd-Ruatha: "Zip it, pinhead, I gotta' warn my uncle."