The Sunagawa Case (1959) — US-Japan Security Treaty and the Political Question Doctrine

Introduction

The Sunagawa Case (Saiko Saibansho, Grand Bench, December 16, 1959) is the foundational Japanese authority on the political question doctrine and the justiciability of treaties under the Constitution of Japan. The case arose from protests against the expansion of the United States military airfield at Sunagawa, a town in what is now part of Tachikawa, Tokyo, and resulted in a landmark judgment that has shaped the Japanese Supreme Court’s approach to national security and foreign relations for over six decades.

The case represents the Supreme Court’s most significant statement on the limits of judicial review under the Constitution and has been the subject of sustained scholarly criticism as an “abdication” of the Court’s constitutional function.

Facts

In 1956, the Japanese government, acting under the US-Japan Security Treaty (Nichi-Bei Anzen Hoshō Jōyaku), commenced proceedings to expand the US military airfield at Sunagawa. The expansion required the compulsory acquisition of land from local farmers and residents, who opposed the expansion on grounds including the alleged unconstitutionality of the presence of US forces in Japan under Article 9 of the Constitution.

Groups of protesters, including political activists, students, and labour union members, entered the base area to block the survey and construction work. They were arrested and prosecuted under the Criminal Law for Special Cases (Tokubetsu Keiji Hō), which criminalised entry into designated US military facilities without authorisation.

The Legal Issues

At trial, the defendants argued that their prosecution was invalid because the US-Japan Security Treaty — the legal basis for both the US military presence in Japan and the special criminal law — was unconstitutional. Specifically, they contended that the Treaty violated:

• Article 9 of the Constitution (renunciation of war and the maintenance of armed forces)
• Article 97 (the fundamental rights of the people as “eternal and inviolable”)
• Article 98 (the supremacy of the Constitution over treaties)

The Tokyo District Court (Presiding Judge Date Akio) accepted the defendants’ argument in 1959, holding that the presence of US forces under the Security Treaty violated Article 9 because it amounted to the maintenance of armed forces and the threat or use of force. The government appealed directly to the Supreme Court under the special appeal (tokubetsu jōkoku) procedure.

The Supreme Court’s Holding

The Supreme Court Grand Bench, in a carefully crafted opinion, reversed the District Court and upheld the constitutionality of the criminal conviction. The Court’s reasoning proceeded in two steps.

First, the Court held that the Security Treaty is a matter of “highly political nature” (kōdono seijisei) and that its constitutionality is “not suitable” (fusuitō) for judicial review. The Court stated: “The determination of whether the Security Treaty is constitutional is manifestly beyond the competence of the court, as it relates to matters of national sovereignty and is of a highly political nature.”

Second, the Court held that even if the Treaty were reviewable in principle, it would be presumed constitutional because it was concluded by the Diet, which is the supreme organ of state power, through the treaty-making procedure prescribed by the Constitution.

The Political Question Doctrine

The Sunagawa Case established the political question doctrine (seijiteki mondai no riron) in Japanese constitutional law. The doctrine holds that certain categories of disputes — particularly those concerning foreign relations, national security, and the structure of government — are unsuitable for judicial resolution because they involve discretionary judgments that are committed to the political branches.

The Court identified the following factors as relevant to determining whether a question is political:

• The nature of the issue (whether it involves a policy judgment that is not amenable to judicial criteria)
• The constitutional commitment of the issue to the political branches
• The institutional competence of the courts to resolve the issue
• The consequences of judicial intervention

The Sunagawa political question doctrine has been applied in subsequent cases to bar judicial review of:

• The constitutionality of the Self-Defense Forces (SDF)
• The constitutionality of the US-Japan Status of Forces Agreement
• The deployment of the SDF overseas (though the Court has engaged with the merits in some subsequent cases)
• The delimitation of electoral districts (though the Court later abandoned the political question doctrine in this context)

The “Act of Government” Doctrine

The Sunagawa Case is also associated with the “act of government” (kōmu kōi) doctrine, which holds that certain acts of the executive — particularly in foreign relations and national security — are not subject to judicial review because they are political acts of sovereignty. The Court’s reference to the Treaty as “manifestly beyond the competence of the court” reflects this doctrine, which is derived from the French acte de gouvernement and the German Regierungsakt theories.

Japanese scholars have criticised the “act of government” doctrine as inconsistent with Article 81 of the Constitution, which vests the Supreme Court with the power to determine the constitutionality of “any law, order, regulation, or official act.” If a treaty is an “official act,” the argument runs, the Court has the constitutional duty to review its constitutionality.

Criticism

The Sunagawa Case has been the subject of sustained and heavy criticism from Japanese constitutional scholars. The principal criticisms are:

• Abdication of constitutional review: The Court’s refusal to review the constitutionality of the Treaty violates its duty under Article 81 of the Constitution
• Inconsistent jurisprudence: The Court has reviewed less politically sensitive matters while refusing review of the most consequential constitutional questions
• Flawed reasoning: The presumption of constitutionality for treaties has no basis in the text or structure of the Constitution
• Undermining the rule of law: The exclusion of entire categories of government action from judicial review contradicts the principle that all government action is subject to constitutional constraints

Lasting Impact

The Sunagawa Case has had a profound and lasting impact on Japanese constitutional law. The Supreme Court has consistently refused to review the constitutionality of the Security Treaty and has applied the political question doctrine to bar review of the SDF’s constitutionality in subsequent cases, including the Naganuma Case (1973) and the Ishida Case (1973).

The case has also influenced the broader relationship between the courts and the political branches. The Supreme Court’s general reluctance to exercise robust judicial review — particularly in matters of national security, taxation, and social welfare — can be traced in significant part to the Sunagawa precedent.

However, the political question doctrine has been narrowed in some contexts. In the Kurokawa Case (1976) and subsequent electoral districting cases, the Supreme Court abandoned the political question doctrine and engaged in substantive review of the constitutionality of malapportionment. This suggests that the doctrine is not absolute but is applied selectively depending on the nature of the constitutional right at stake.

Conclusion

The Sunagawa Case remains the cornerstone of the Japanese political question doctrine and a defining statement of the Supreme Court’s conception of the limits of judicial power. Its holding that the constitutionality of treaties — particularly security treaties — is not suitable for judicial review has been consistently followed for over sixty years. While criticised as an abdication of judicial responsibility, the case continues to shape the Japanese constitutional landscape, reflecting a judicial philosophy that emphasises restraint, deference to the political branches, and institutional self-preservation.