The ability of modern science to isolate Deoxyribonucleic Acid (DNA), has served to virtually revolutionize the criminal justice system. In simple terms, prior to this technology, the most unassailable evidence in the trial process was limited to that of eyewitness testimony and/or electronic surveillance, both of which may be subject to lacks of credibility. Witness account are inherently subjective, even when most seemingly accurate; then, video and audio recordings are frequently of poor quality, or inadmissible when obtained in a manner inconsistent with the rights of a defendant.With the widespread acceptance of DNA as established science in the 1980s (Chambliss, 2011, p. 14), the courts were finally able to employ scientifically and legally irrefutable evidence.
The advantages to this technology are as numerous as any derived from so unimpeachable a means of gaining proof of crime. Moreover, they go well beyond convictions, in that the offender identified by DNA is so conclusively known, there is virtually no possibility of a wrongful verdict being reached. As DNA is intrinsically a material with properties purely unique to each individual, multiple suspects in certain cases may be safely removed from consideration, making DNA a valuable tool in all investigative, pre-trial procedures. Not only does DNA, then, eliminate the potential for incorrectly obtained convictions, it has been used to exonerate several hundred inmates wrongfully imprisoned (Huff, Killias, 2008, p. 45). Above all, however, DNA provides, as noted, the insuperable advantage of arming the criminal justice system with a form of evidence not open to dispute.
These assets notwithstanding, there are disadvantages, or potential risks, in using DNA within the criminal justice system, and particularly in the courtroom phase. One is the inevitable factor of human error within the testing process. No matter how rigid the testing parameters and conditions, there is always a risk of contamination and, in cases involving capital offenses, it is to be expected that the defense will seize upon any such possibility. This was used to dramatic effect in the O. J. Simpson trial of 1995, when the defense team obtained an innocent verdict by challenging the accuracy of the DNA taken from the crime scene (Kobilinsky, Liotti, Oeser-Sweat, 2005, p. 252). Consequently, it appears that even a form of evidence as precise as DNA may be ineffective in criminal justice, as absolute integrity of gathering and testing must be proven to assert integrity of content. This possibility of damaged or contaminated DN evidence, albeit minimal, goes to another disadvantage, that of properly acquainting a jury with the science it requires to understand, and consequently trust, the DNA evidence presented to it.