Wow, really have to thank R.R. for the New Mexican case in which polygraph evidence WAS admitted in court. I was totally unaware until now of ANY U.S. jurisdiction in which polygraph evidence was admissible. The Wikipedia article on admissibility of polygraph evidence is clear that this evidence is barred from any Canadian courtroom by virtue of a Supreme Court of Canada decision, also that whereas the Supreme Court of Australia has not yet ruled on the issue, the highest State court to rule on the issue (New South Wales) has barred the use of polygraph evidence and in Europe generally the use of the polygraph is not even common in police forces. In Germany, no court can use polygraph evidence.
According to Wikipedia, the picture in the U.S.A. is less clear. New Mexico seems to be the only state to allow polygraph evidence before juries; however it seems that 19 states (roughly 40%) will allow polygraph evidence by stipulation, which I imagine means if both parties are willing to admit it. If I'm correct in this, it's certainly an indication that even the 19 states that admit polygraph evidence by stipulation don't think very highly of the technique - - can you imagine any court today that is willing to admit, say, fingerprint, or DNA, or ballistics or Breathalyzer evidence by stipulation only?
So instead of polygraph evidence being barred in EVERY court, it's basically barred in MOST courts. Whether police use it or not is ridiculously irrelevant, unless you believe that it's OK to let the police determine anyone's guilt or innocence and courts aren't really necessary. Well, actually, since I am dealing with hard-core conservatives here, maybe that is exactly how they DO feel.
I think the overall picture on polygraphs is generally as I originally stated it, only instead of NO courts admitting polygraph evidence, it turns out that one state (New Mexico) will admit it, and 19 others will do so by stipulation, which still indicates an extremely low opinion of the quality of that evidence. Polygraphs are still regarded as junk science by the majority of jurisdictions in the USA, Canada, Europe and Australia. Also, it seems (from the same article) that the High Court of Israel has ruled that the polygraph has not been recognized as a reliable device.
The Wikipedia article referred to is here:
http://en.wikipedia.org/wiki/Polygraph#United_StatesAnd of course the National Research Council's extensive study of the polygraph from 2002 still stands as further evidence that the polygraph is still what the courts of most jurisdictions consider it to be, i.e., junk science.
The voice stress analysis ("VSA") is, IMHO, of even lower reliability than the polygraph, so the so-called "lie detector" test which The Perv purportedly passed and one of his victims purportedly failed, is junk science even lower than polygraph junk science. Thanks to plane for the VSA evaluations he had dug up, which I haven't had time to review yet, but will get around to very soon.