International and constitutional law are becoming increasingly intertwined, and scholars have begun to focus on the role of national constitutions in the international context. This book is an essential academic contribution that significantly enhances discussion among international and constitutional lawyers. It draws on extensive research of American, German, and Japanese literature and case-law to compare the role of domestic parliaments and national courts. Yamada carefully considers key concepts such as the democratic deficit, self-executing doctrine, the Charming Betsy Canon, direct and indirect application of international law, Völkerrechtsfreundlichkeit, and judicial dialogue. This book review tries to contextualize Yamada’s achievements in international legal scholarship in Japan; namely, the long-standing prominent works of Japanese international lawyers Takano Yuichi and Iwasawa Yuji.

Yamada’s book comprises two parts. The first part involves a comparative discussion of domestic parliaments in the globalized era. It carefully analyzes Japanese, German, and American academic literature from the standpoint of domestic democratic legitimacy. Yamada asserts that Japan can learn from Germany and the United States [US], and strengthen parliamentary involvement in enacting international law. For example, Yamada proposes introducing the US-style fast-track procedure in Japan. While reducing parliamentary involvement in treaty approval, the fast-track procedure encourages legislative involvement by providing information to the Diet during the processes of treaty negotiation. Yamada argues that the fast-track procedure is beneficial for the rapidity of diplomacy and parliamentary democratic control. He also suggests utilizing the administrative procedure to enhance democratic control of international norms (p. 186).

The second part of Yamada’s book analyzes the role of domestic courts in the globalized context, in particular the self-executing doctrine and Charming Betsy Canon in the US, as well as the principle of Völkerrechtsfreundlichkeit in Germany. Based on careful analysis of German literature, Yamada suggests that “direct applicability” can offer an arena for co-ordinating different legal systems (pp. 439–40). Yamada further attempts to reconstruct the interpretation of Article 98(2) of the Japanese Constitution, which stipulates that “[t]he treaties concluded by Japan and established laws of nations shall be faithfully observed”. The prevailing view in Japan maintains that both customary and treaty laws acquire domestic effect through Article 98(2) of the Constitution, and they are ranked higher than statutory law, but lower than the Constitution. Contrary to the prevailing view, Yamada argues that international norms are ranked equal to statutory law in Japan, and Article 98(2) merely supports an interpretation in which domestic statutes are compatible with international rules (p. 459). Yamada also attempts to reconsider the idea of “dialogue” from the perspective of democratic legitimacy (p. 473).

Although this reviewer does not fully agree with the arguments put forward regarding the interpretation of Article 98(2), there is no doubt that this book serves as an important bridge between constitutional and international theories. It offers an important perspective through which one can analyze contemporary issues regarding the implementation of international obligations and constitutional democratic legitimacy. The relationship between treaties and constitutional law was the focus of the canonical book written by Takano Yuichi more than half a century ago.Footnote ¹ Through analyzing European (namely French) literature and case-law, Takano established an academic foundation in this field. Takano’s former student and prominent Japanese international lawyer, Iwasawa Yuji, critically enhanced Takano’s argument in 1985 through extensive comparative analysis with European and US cases.Footnote ² The works of these international lawyers provided a framework to realize the proper domestic implementation of international obligations. However, these works did not thoroughly analyze parliamentary or executive involvements in implementing international obligations from a constitutional perspective.

Based on his extensive knowledge of international law, Yamada has greatly enriched scholarship by analyzing the issues from a constitutional perspective; namely, parliamentary and executive engagement, and democratic legitimacy. Yamada’s book overcomes the court-centred mindset in international legal scholarship. It enables readers to acquire substantial and multilayered perspectives to better understand the interaction between international and constitutional law. Perhaps it is time for both constitutional and international lawyers to tackle another mindset—European centrism—by extending comparative research to Asia and other regions.Footnote ³ The Asian Society of International Law should play a central role in providing an academic forum to pursue this aim.

Professor Yamada graduated from Kyoto University, Faculty of Law (LLB in 2007, JD in 2009, and PhD in 2012). He currently holds an Associate Professorship at Okayama University Graduate School of Humanities and Social Sciences / Faculty of Law and publishes papers in both Japanese and English.Footnote ⁴