REVISITING THE TU QUOQUE DEFENCE: THE S.S. LOTUS CASE AND ITS RELEVANCE TO CONTEMPORARY INTERNATIONAL LAW

Authors : Gonca Ünal

Pages : 481-512

Doi:10.54704/akdhfd.1800417

View : 42 | Download : 318

Publication Date : 2026-01-23

Article Type : Research Paper

Abstract :The S.S. Lotus case (1927) is often cited as the archetype of positivist reasoning in international law, establishing the principle that what is not expressly prohibited is permitted. Yet this reading overlooks a subtler layer of normative reasoning within the judgment. This article revisits Lotus through the lens of the tu quoque argument, commonly dismissed as a fallacy or an obsolete defence in international criminal law. It argues that Turkey’s reliance on provisions borrowed verbatim from the Italian Penal Code and procedural doctrines from the French Code of Criminal Procedure operated as a soft legitimation strategy, implicitly asserting parity with European legal systems. In doing so, Turkey’s argument performed a reflexive form of legality. If Turkey’s law were inconsistent with international norms, so too would be the very European sources from which it was drawn. Building on Sienho Yee’s typology and Hersch Lauterpacht’s reflections on ‘uncertain situations’ the study shows how tu quoque transcends its narrow criminal law context to function as a discursive mechanism of normative balancing in asymmetrical legal orders. The article situates this within the interwar moment of international adjudication, when sovereignty, imitation, and legality intertwined in the making of modern international law. Ultimately, the study proposes that the tu quoque argument far from being a mere plea of exculpation retains analytical value for understanding legitimacy and reciprocity in contemporary international law, including emerging fields such as cyber and space regulation. Revisiting Lotus thus illuminates the enduring tension between legality, legitimacy, and equality among sovereigns.
Keywords : S.S. Lotus Davası, Tu Quoque Savunması, Meşruiyet, Mütekabiliyet, Egemenlik, Taklit, Asimetri, Normatif Tutarlılık, Savaşlar Arası Hukuk

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