When a defense attorney takes on a capital case, one piece of ammunition that can sway the court is the polygraph examination. While the polygraph examination is believed to not be admissible, there are misconceptions about how and when to use the test. Today, we will break apart the concept of the polygraph and explain how the exam can be the difference between incarceration or freedom.
We start with an understanding of what the polygraph is. If we were to look up the term in Black’s Law Dictionary, we learn that a polygraph is defined as: a machine designed to detect and record changes in physiological characteristics, such as a person’s pulse and breathing rates, used especially as a lie detector. In essence, the polygraph is a key to tell the prosecution if a defendant is telling the truth and while the test is not admissible as a general rule, there are major exceptions that a strong criminal defense attorney should be aware of.
To begin, the polygraph may not be admissible at trial without a stipulation from all parties but it can be used by defense counsel to argue for a new trial and also can play a vital role at sentencing. More importantly, the polygraph can carry a great deal of leverage in the pretrial stages which can set the tone for the outcome of the case.