We could start with a standard of not willfully lying about facts and see how it goes. I agree that the gray areas could get tricky, but just starting with most

We could start with a standard of not willfully lying about facts and see how it goes. I agree that the gray areas could get tricky, but just starting with most obvious cases might provide a lot of the benefit. I think the current status quo, where cops can lie to citizens about anything and everything with no consequence, is pretty bad. Sure it might help with some specific convictions, but the immense lack of trust and goodwill that generates in the entire public must cause a huge amount of harm and lose a number of other solvable cases. Even though I'm not engaged in any criminal enterprises I am still wary about saying anything to police. Even though most police are decent people, mistakes happen and they are often under pressure to hit certain metrics. Indictments of innocent people are hardly rare and you never know what a cop's angle is, given their freedom to lie at will.