Across diverse legal traditions, the search for truth is a basic function of the criminal process. Uncovering the truth about the charged crime is regarded as an essential precondition to achieving justice, enforcing criminal law, and legitimating the verdict. Yet while truthseeking is a broadly accepted goal in the criminal process, no system seeks the truth at all costs. The search for truth must on occasion yield to considerations related to efficiency, democratic participation, and protection of individual rights.
Different jurisdictions around the world show different preferences with respect to the tradeoffs between these values and the search for truth in criminal procedure. In an effort to promote efficiency, enhance democratic participation, or protect individual rights, many legal systems tolerate certain procedures that are known to heighten the risk of inaccurate outcomes. Such truth-impairing procedures include the exclusion of unlawfully obtained evidence, plea bargaining, and unreviewable jury verdicts. To some degree, the extent to which a legal system embraces these procedures can be explained with reference to the influence of the adversarial and inquisitorial traditions. But the distinction between adversarial and inquisitorial systems on this point is not always clear. Great variation exists within these two traditions, and common approaches can be seen across the divide.
Some truth-limiting procedures, such as those related to the exclusionary rule and the protection of individual rights, have been adopted largely across the globe and have proven amenable to adjustments that accommodate the concern for truth. Other measures, such as lay participation in the criminal process, have retained their hold in some countries but have not spread to many others. Finally, one category of practices generally acknowledged to conflict with truthseeking — plea bargaining and other methods of negotiated justice — have become increasingly prevalent, but have proven the most difficult to regulate and to align with the search for truth.
Jenia I. Turner, Limits on the Search for Truth in Criminal Procedure: A Comparative View, in Comparative Criminal Procedure (Jacqueline Ross & Stephen Thaman eds. 2016)