Polygraph evidence is included within the broad category of expert testimony, yet it is treated quite differently from other forms of expert testimony. If admissible at all for the defense, polygraph evidence almost always requires the stipulation of the prosecution for it to be admitted into court. Such a requirement vests solely, within the hands of a prosecutor, the ability to eliminate that proof which may be necessary for the defendant to effectively prove his innocence. Furthermore, in some jurisdictions a defendant cannot even place his faith in the sympathy of a prosecutor. Instead, a rule bars him from proving his innocence. Such rules and requirements may very well deny the defendant his constitutional right to compulsory process.
Walsh, Timothy J.
"Polygraph Admission Through Compulsory Process,"
Akron Law Review: Vol. 16
, Article 8.
Available at: https://ideaexchange.uakron.edu/akronlawreview/vol16/iss4/8