What is the legal limit of coercive force, both psychological and physical, that a suspect in police custody can be subjected to? This would apply to both before and after a lawyer is requested/appointed.
I am under the belief that there is no obligation for police interrogators to tell the truth to suspects, and any amount of psychological manipulation is permissable in obtaining evidence/confessions. Is this correct?
You must be advised of your rights before the results of any questioning may be used against you. Those rights include the right to an attorney, including one appointed for you if you cannot afford an attorney, the right to remain silent, and the right to cease answering questions at any time during the interrogation.
Once you have been advised of those rights, the police may, as the OP surmises, lie to you in order to secure a confession.
I’m not so sure “any amount” of psychological manipulation is permitted, but I suspect the confusion arises because I am not sure what you mean by “psychological manipulation.” For example, the police may not tell you your family will be killed if you fail to immediately confess. Since they cannot, in fact, kill your family, one may characterize this as “psychological manipulation,” and tactics of this type are absolutely impermissible.
On the other hand, the police may, for example, legitimately prey on your religious guilt, suggesting that God would want you to confess. That sort of psychological manipulation is permitted.
So I guess it comes down to – what do you mean by the term?
By the term “psychological manipulation” I meant things that didn’t cause physical harm. Although I can see how the threat of violence could be considered psychological, I mainly thought of threats of violence as physical in nature.
If I may clarify, after being advised of one’s rights, a suspect may be subjected to shouting, guilt tactics, increased temperatures, confinement, mutterings of “we will do whatever it takes to secure your confession”?
The reason I ask this question, is because I am trying to determine if the Geneva Conventions are more strict in prisoner handling than the U.S. justice system.
That to me seems more restrictive than what suspects within the U.S. are subject to. Would that be a fair assessment?