I really don't believe a lie detector would have such drastic effects simply because the motive of hate is too strong. Lie detectors probably would not have stopped Napoleon, Alexander the Great, Julius Caesar, Joseph Stalin (would have made his job easier, but the job would still exist), Adolf Hitler, Genghis and Kublai Khan.
Do you think a lie detector would have stopped the Crusades?
Muslims: Are you going to invade the Holy Land?
Christian Knight(with thousands of soldiers standing behind him): Yes.
Muslims: No! Don't!
Christian Knight: Oh well since you said no, we'll just leave...spare any whores?
There would never be another invasion of a country, at least one that the world wouldn't know about it ahead of time, because they would never be able to hide it.
You'll need a time machine and a lie detector to know who to ask and when to ask it. Do you know which land is going to be invaded next? If you had a lie detector would be able to stop it?
Politicians would entirely have to be honest, because all fibs would be detected.
How would your lie detector become totally knowledgable of a politicians dealings if you don't know what questions to ask?
Lie D.: Senator, are you embezzeling money out of commitee budget?
Senator: No.
Lie D.: He's telling the truth.
Senator thinks to himself: I'm glad he didn't ask about the secret approval I gave to 3 commandos to assassinate a leader of a gun smuggling ring on the border of China and Vietnam.
Lie D.: Congressman, did you authorize the facilitation of a drug deal in order to get information out of an informant for the DEA?
Congressman: Nope
Lie D.: clear
Congressman thinks: I just sleep with my secretary and her underage daughter.
Lie D.: Mr. President, are you hiding something?
President: No.
Lie D.: You are lying.
President: Yes I am, and good luck finding out what I am hiding.
President thinks to himself: In college I exprimented with lots of men.
Even such moral issues as cheating on your spouses would almost be eliminated.
If you think you need to ask your spouse about infedility, the relationship is just about over. If she says yes, it's over. If she says no, and she had any self respect, she'd end it with you or just start cheating on you cuz she knows you're suspecting her anyway.