314
Opinion of Thomas, J.
weight to the opinions of a polygrapher, clothed as they are in scientific expertise and at times offering, as in respond-ent's case, a conclusion about the ultimate issue in the trial. Such jurisdictions may legitimately determine that the aura of infallibility attending polygraph evidence can lead jurors to abandon their duty to assess credibility and guilt. Those jurisdictions may also take into account the fact that a judge cannot determine, when ruling on a motion to admit poly-graph evidence, whether a particular polygraph expert is likely to influence the jury unduly. For these reasons, the President is within his constitutional prerogative to promulgate a per se rule that simply excludes all such evidence.
C
A third legitimate interest served by Rule 707 is avoiding litigation over issues other than the guilt or innocence of the accused. Such collateral litigation prolongs criminal trials and threatens to distract the jury from its central function of determining guilt or innocence. Allowing proffers of polygraph evidence would inevitably entail assessments of such issues as whether the test and control questions were appropriate, whether a particular polygraph examiner was qualified and had properly interpreted the physiological responses, and whether other factors such as countermeasures employed by the examinee had distorted the exam results. Such assessments would be required in each and every case.10 It thus offends no constitutional principle for the President to conclude that a per se rule excluding all poly-graph evidence is appropriate. Because litigation over the admissibility of polygraph evidence is by its very nature col-10 Although some of this litigation could take place outside the presence of the jury, at the very least a foundation must be laid for the jury to assess the qualifications and skill of the polygrapher and the validity of the exam, and significant cross-examination could occur on these issues.
Page: Index Previous 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 NextLast modified: October 4, 2007