A New Perspective on the judge’s disqualification for Substantive opinion; A Comparison of Criminal Procedure in Iran and the U.S. Federal System

Document Type : Research Paper

Author

Assistant Professor, Department of Law, Faculty of Humanities, University of Shahed, Tehran, Iran.

10.22034/law.2026.68117.3505

Abstract

The impartiality of judicial authorities is a fundamental principle of criminal procedure. One manifestation of this principle is the statutory recognition of grounds for judicial recusal. Article 421 of Iran’s Code of Criminal Procedure identifies a judge’s prior substantive opinion on a case as one such ground. However, Ruling No. 517 of the Iranian Supreme Court, which categorizes a judge’s preliminary opinions on a defendant’s prosecutability (e.g., during objections to a dismissal order or in resolving disputes between investigators and prosecutors) as procedural rather than substantive, raises significant legal questions. Is this ruling consistent with established legal norms? Can such opinions genuinely be characterized as non-substantive? Does judicial scarcity justify this interpretive approach? This study examines the conditions for recusal due to prior substantive opinions, analyzing their legal nature through a descriptive-analytical methodology. Comparative insights—particularly from U.S. federal law (28 U.S. Code §§ 47 and 455, which govern judicial disqualification)—enrich the analysis. Findings reveal that while both legal systems share commonalities, U.S. jurisprudence adopts a broader interpretation of recusal grounds, emphasizing impartiality as a decisive criterion. The U.S. framework encompasses additional scenarios where bias or partiality may arise, underscoring a more rigorous commitment to judicial neutrality.

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