Apparently the justices of the Supreme Court like to have their cake and eat it too. Or, so it seems from today's opinion on identifications in criminal cases.
In an eight-to-one opinion, the Supreme Court of the United States today limited a criminal defendant's right to challenge an eyewitness's claim that he saw the defendant commit a crime. The case, Perry v. New Hampshire [pdf], involves a pre-trial procedure challenging an eyewitness identification through a motion to suppress.
Motions to suppress identification have the effect, if granted, of preventing evidence of an out-of-court identification from ever reaching a jury at a trial. At times, they may even have the effect of preventing an eyewitness from identifying a defendant during the trial as the perpetrator of the crime.