Admissibility of evidence in the US criminal procedure system

The article considers the basic institutes of evidence law in the US criminal procedure system, focusing specifically on the field of admissibility of evidence in criminal court trials. American legal theory does not recognize the rigorous definition of evidence and, in principle, will generically accept any kind of source of cognition which can be of use to prove or disprove the existence of relevant fact regarding the guilt or innocence of the accused. Despite such broad understanding of evidence, the US legal system has accepted rigorous evidence rules in the matter of using evidence as a source of cognition in courtrooms. Categories like relevancy, reliability, competency and exclusion of prejudicial effect represent general or specific conditions which evidence as a legal construction has to fulfill in order to be admissible. The mentioned categories are the substance of the evidence law in United States and formally unavoidable mechanism in the opening, conducting and completing a criminal procedure with a legally justified decision. In addition to the basic remarks about the characteristics of US evidence law, the author also presents the general approach of American legal theory to the notion of evidence, some theoretical and legal classifications and definitions of certain kinds of evidence. Finally, particularly analytical focus has been put on the specific conditions of admissibility of evidence in US criminal court trial.