Conduct research into how restricted the use of polygraph evidence within the justice system is. The admissibility and legally authorized use of polygraphs both in and out of the justice system itself has evolved over the years. Your research does not have to be limited to admissibility in court. Polygraph machines continue to be employed regularly in the private sector, raising the question of whether a machine that is not 100 percent foolproof can be considered an unconstitutional invasion of privacy.
One of the most important topics for a paper on the criminal justice system is the criteria for admissibility of evidence in a criminal case. This paper would delve into the real-world application of Fourth Amendment rights by law enforcement officials. Other areas that should be explored are the rules and regulations regarding the collecting of evidence from a crime scene as they relate to tainting that evidence.
The criminal justice system does not necessarily verge into the territory of contract law, but you can make that leap when writing a research paper. Conduct research into whether the unnecessarily obtuse legal jargon used in contracts can lead to an unwitting commitment of an offense by a layman who simply did not understand the language of the writing. This paper could be taken to the next level by researching movements to require that contracts be written using a plainer form of English so that the average client can understand what he is signing.
Research the often qualified and unclear alibis of duress and necessity. Duress is an appropriate alibi when a person has been made to commit an illegal act due to unlawful pressure from another person. Necessity is similar, with the exception that the duress that forces a person to necessarily commit a crime is created not by another person but rather external natural forces. The research here can focus on the language that is used in writing these exceptions into law and whether they can be too easily exploited by the guilty or whether they are so strict that they can rarely even be used by the innocent.