Measures to Ensure Prosecutorial Disclosure of Evidence and Its Relation to the Adversarial System: A Comparison and Analysis of Practices and Approaches in Various U.S. Jurisdictions

2023 Fiscal Year Final Research Report

• Project/Area Number: 18K12663
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 05050:Criminal law-related
• Research Institution: Chuo University (2023); University of the Ryukyus (2018-2022)
• Principal Investigator: Miake Sho 中央大学, 法学部, 准教授 (60635176)
• Project Period (FY): 2018-04-01 – 2024-03-31
• Keywords: 証拠開示 / 刑事訴訟法 / 当事者手技 / 検察官 / アメリカ合衆国 / デュープロセス / 公正な裁判

Outline of Final Research Achievements

By comparing the practices and measures related to criminal discovery in various U.S. jurisdictions (federal and state level), this research aims to gain insights into (1) how to ensure prosecutors fulfill their obligation to disclose evidence, and (2) the relationship between prosecutorial disclosure and the adversarial system. It analyzes various approaches at different levels to ensure that prosecutors fulfill their constitutional obligation to disclose material evidence favorable to the defense under Brady v. Maryland. It also examines the validity of the Open-File Discovery legislation adopted in some states, which obligates prosecutors to disclose an extensive range of evidence collected during the investigation and prosecution of the case. The findings were presented at a workshop of the Criminal Law Society of Japan and published in several papers.

Free Research Field

刑事訴訟法

Academic Significance and Societal Importance of the Research Achievements

証拠開示を検察官に法律等で義務づけても、それを現実に担保することは容易ではない。アメリカでは1963年より被告人に有利で重要な証拠の開示は憲法が要求すると解されている一方（Brady法理）、誤判の原因として証拠の不開示が寄与していたと考えられる事件も数多く判明したことなどから、この問題に対し様々なアプローチの取組みがみられる。中には検察側が事件の捜査・訴追の過程で収集した証拠を原則全て開示することを義務づけた州もある。そうした取組みの有効性や、証拠開示と当事者主義の関係を分析したことは、同じく当事者主義を採用し、証拠開示制度を持つわが国にとって制度の点検や改革を行う上で示唆に富む。