Q: What is the procedure for amending the Japanese Constitution, and are there any theoretical limits to such amendments?

A nation's constitution serves as its foundational legal document, embodying its core principles and structuring its governance. While designed for stability, constitutions must also possess mechanisms for adaptation to evolving societal values and circumstances. This process of formal change is known as constitutional amendment. The Constitution of Japan, notable for having never been amended since its enactment in 1947, prescribes a particularly stringent procedure for such alterations. Beyond the procedural hurdles, a significant and ongoing debate exists within Japanese constitutional law regarding whether there are inherent, substantive limits to what can be changed, even if the formal amendment process is followed. This article delves into the amendment procedure stipulated in the Japanese Constitution and explores the complex theoretical arguments surrounding these potential limitations.

The Concept of Constitutional Amendment

Constitutional amendment (kenpō kaisei - 憲法改正), in its formal sense, refers to the modification of the text of the existing constitution through a specific, legally prescribed process outlined within the constitution itself. This formal amendment is distinct from other forms of constitutional change, such as "constitutional transformation" (kenpō hensen - 憲法変遷), which refers to substantive changes in the meaning or application of constitutional provisions without textual alteration, or the more radical overthrow of a constitutional order through extra-constitutional means like a revolution or coup d'état. Amendments can take various forms, including the revision of existing articles, the deletion of provisions, the addition of new articles, or, more comprehensively, a complete rewriting of the document. However, whether a "total revision" truly falls under the concept of "amendment" or constitutes the creation of a new constitution is itself a point of theoretical contention, especially when fundamental principles are altered.

The Rigorous Amendment Procedure: Article 96

Article 96 of the Constitution of Japan meticulously lays out a multi-stage process for amendment, reflecting its character as a "rigid" or "hard" constitution, designed to be more difficult to alter than ordinary statutes:

1. Initiation by the National Diet (Kokkai no Hotsugi - 国会の発議):
   An amendment must first be initiated by the National Diet. This requires a concurring vote of a supermajority: two-thirds or more of all the members of each House (the House of Representatives and the House of Councillors).
   • The term "all the members" (sōgiin - 総議員) is generally interpreted in practice to mean the full legal quota of members for each House, rather than merely those present and voting or those currently holding seats (which might be fewer due to vacancies). This high threshold makes initiating an amendment a significant political undertaking, requiring broad cross-party consensus.
   • Draft amendments can be proposed by Diet members. The Diet Law stipulates that such proposals require the support of 100 or more members in the House of Representatives and 50 or more members in the House of Councillors (Diet Law, Art. 68-2). The Commissions on the Constitution (Kenpō Shinsakai - 憲法審査会), established in each House, also play a role in researching and deliberating on the Constitution and potential amendments, and can submit draft proposals (Diet Law, Art. 102-7).
   • Whether the Cabinet has the authority to formally propose constitutional amendments is a debated point in Japanese constitutional law, with no explicit provision granting such power. Current practice leans towards initiation by Diet members.
2. Submission to and Ratification by the People (Kokumin no Shōnin - 国民の承認):
   Once initiated by the Diet, the proposed amendment must be submitted to the people for ratification. This takes the form of a special national referendum (tokubetsu no kokumin tōhyō - 特別の国民投票) or such election as the Diet specifies.
   • Ratification requires the affirmative vote of a majority of all votes cast in that referendum. This means a simple majority of those who actually vote on the proposal, with blank or invalid ballots typically not counted towards the denominator.
   • The detailed procedures for this national referendum are stipulated in the "Law Concerning the Procedures for Amendment of the Constitution of Japan" (Nihonkoku Kenpō no Kaisei Tetsuzuki ni Kansuru Hōritsu - 日本国憲法の改正手続に関する法律), often referred to as the National Referendum Law (Kokumin Tōhyō Hō - 国民投票法). This law, enacted in 2007 and fully effective from 2010, covers aspects such as voter eligibility (currently 18 years of age and older, in line with general election law), the scope of permissible campaign activities, and the administration of the referendum.
3. Promulgation by the Emperor (Tennō no Kōfu - 天皇の公布):
   If the proposed amendment is ratified by the people, it is then immediately promulgated by the Emperor in the name of the people, as an integral part of the Constitution (Article 96, paragraph 2; Article 7, item 1).
   • The Emperor's role in promulgation is purely formal and ceremonial; it does not involve any substantive approval or discretion regarding the amendment's content. This reflects the principle of popular sovereignty where the ultimate authority for constitutional change resides with the people.

The stringency of this multi-layered process, particularly the two-thirds requirement in both Houses of the Diet and the necessity of a national referendum, underscores the high value placed on constitutional stability and the broad consensus deemed necessary for fundamental legal change. To date, this high bar has meant that the Constitution of Japan has remained unamended since its promulgation.

The Theoretical Debate: Are There Limits to Constitutional Amendment?

Beyond the formal procedures, a profound theoretical debate in Japanese constitutional scholarship concerns whether there are substantive limitations (kenpō kaisei no genkai - 憲法改正の限界) on the power to amend the Constitution. Even if the rigorous process of Article 96 is flawlessly followed, can any provision of the Constitution be altered, or are certain core principles sacrosanct and unamendable?

1. The Unlimited Amendment Theory (Mugen Kaisetsu - 無限界説):
   This theory posits that there are no substantive limits to constitutional amendment. As long as the formal procedures laid down in Article 96 are adhered to, any part of the Constitution, including its most fundamental principles, can be changed, added to, or deleted. The rationale often cited is that the amending power, ultimately reflecting the will of the sovereign people, is supreme and cannot be bound by the content of the existing constitution. Another argument is that all constitutional norms are qualitatively equal, with none inherently superior or unamendable.
2. The Limited Amendment Theory (Genkai Setsu - 限界説):
   This is the prevailing view among Japanese constitutional scholars. It argues that certain fundamental principles or core elements of the Constitution are inherently unamendable, even through the formal procedures of Article 96. The reasoning for such limitations typically follows one of two main lines:The Preamble of the Japanese Constitution, which declares fundamental principles such as popular sovereignty, respect for human rights, and pacifism, is often cited as a textual anchor for identifying these unamendable core elements.
   • Supra-Positive Law / Natural Law Argument: This perspective holds that certain universal values, such as popular sovereignty, respect for fundamental human rights (especially human dignity), and pacifism, are either reflections of natural law or have achieved a supra-positive legal status, making them hierarchically superior to the written text of the Constitution itself. Attempting to amend these core tenets would be to negate the very essence of a modern constitutional democracy and would therefore be impermissible.
   • Distinction between Constituent Power and Amending Power: This influential argument distinguishes between the original pouvoir constituant (constituent power)—the power that creates a constitution, seen as residing in the "people" in a foundational sense—and the pouvoir constitué (constituted power), which includes the power to amend the constitution as granted by that constitution. The amending power, being a delegated and constituted power, cannot be used to destroy or fundamentally alter the core decisions and identity established by the original constituent power. This would include changing the locus of sovereignty (e.g., from the people to a monarch) or abolishing the fundamental principles upon which the constitutional order is based.

Specific Issues within the Limitation Debate:

• Amending Article 96 Itself: Can the stringent amendment procedure of Article 96 be made less rigid through an amendment? Proponents of the limited amendment theory generally argue that while minor procedural adjustments might be permissible, an amendment that fundamentally weakens the process (e.g., significantly lowering the Diet supermajority requirement or abolishing the national referendum) would be unconstitutional because it would undermine the principle of popular sovereignty and the stability that a rigid constitution is meant to ensure.
• Total Revision (Zenbu Kaisei - 全部改正): Is a complete rewriting of the Constitution permissible under the guise of "amendment"? Some argue that the term "amendment" inherently implies continuity with the existing constitutional framework, and a total revision would effectively be the creation of a new constitution, an act exceeding the amending power. Others maintain that the focus should be less on the extent of textual change and more on whether fundamental principles are being abrogated.
• Absence of "Eternity Clauses": Unlike some constitutions (e.g., Germany's Basic Law, which explicitly protects human dignity and democratic principles from amendment), the Japanese Constitution contains no such "eternity clauses." However, proponents of inherent limitations argue that these limits are implicit in the very nature of constitutionalism and the foundational principles adopted by the Japanese people.

The Status of an "Unconstitutional Amendment" and Judicial Review

If an amendment were enacted that transgressed these theoretical substantive limits, its legal status would be highly contentious.

• Validity: From the perspective of the original constitutional order, such an amendment would be considered invalid, as it would have exceeded the legitimate scope of the amending power. However, if such an "unconstitutional amendment" were to gain widespread public acceptance and effectively establish a new, stable legal order, it might, in practice, be seen as the product of a de facto exercise of constituent power, leading to the birth of a new constitution. The enactment of the current Constitution of Japan itself, through the formal amendment procedures of the Meiji Constitution but fundamentally altering its core principles (e.g., sovereignty), is often analyzed in this light—as a revolutionary change amounting to a new constitutional enactment rather than a mere amendment in the substantive sense.
• Judicial Review of Amendments: A crucial question is whether courts, particularly the Supreme Court, can review the substantive constitutionality of a constitutional amendment that has successfully passed the Article 96 procedures. There is no explicit provision for this in the Constitution.
  • In some jurisdictions, such as Germany, constitutional courts do exercise this power against explicit unamendability clauses.
  • In Japan, the high threshold of popular ratification via referendum might lead to the argument that a duly passed amendment carries such democratic legitimacy that it should be considered a "political question" beyond the scope of judicial review.
  • Conversely, if the amending power is viewed as a power delegated by and under the Constitution, its exercise could theoretically be subject to judicial scrutiny to ensure it remains within its implicit substantive boundaries. If the people acting in a referendum are seen as exercising original constituent power, judicial review becomes problematic. If, however, they are acting as a constitutionally established organ exercising a constituted power, judicial review might be conceptually more tenable, though politically fraught.

Conclusion: Stability and the Unanswered Questions of Change

The Japanese Constitution's amendment procedure under Article 96 is undeniably one of the most stringent in the world, reflecting a strong emphasis on constitutional stability and continuity. This rigidity has contributed to the fact that it has never been amended. However, the absence of amendments does not mean the absence of debate. The theoretical discussions surrounding the substantive limits of the amending power are vibrant and touch upon the very foundations of Japanese constitutionalism: the nature of sovereignty, the hierarchy of norms, and the enduring importance of fundamental principles. While these debates remain largely academic in the absence of concrete amendment proposals reaching the referendum stage, they provide a critical framework for understanding how Japan might navigate profound societal changes that could one day necessitate formal constitutional evolution. The question of whether the will of a current majority can alter the foundational pact of the nation, and if so, to what extent, remains a central, if dormant, issue in Japanese constitutional law.