Sanae Takaichi's rhetoric signals the risks of Japan's evolving security strategy

"Collective self-defense" is one of the forms of self-defense recognized under Article 51 of the UN Charter. It was conceived to prevent the resurgence of fascism and a renewed threat to world peace.

Japan's Constitution formally renounces war and the threat or use of force as a means of settling international disputes. On this basis, the Japanese government claimed to uphold the exclusively defense-oriented principle, under which Japan may employ defensive forces only when it is subjected to an armed attack, and may not exercise the right of collective self-defense.

However, in 2015, Shinzo Abe's cabinet forced new security legislation through the Diet, paving the way for Japan to exercise the right of collective self-defense and asserting that Japan may exercise this right in response to so-called "survival-threatening situation."

Such a "survival-threatening situation" is defined as a case in which a country with close relations to Japan comes under armed attack, thereby posing a clear danger to Japan's survival and fundamentally overturning the Japanese people's rights to life, liberty, and the pursuit of happiness.

Japanese Prime Minister Sanae Takaichi claimed that "a Taiwan contingency" could constitute such a "survival-threatening situation," implying Japan's possible armed intervention in the Taiwan Strait.

As the incumbent prime minister of Japan and supreme commander of the Self-Defense Forces, Takaichi recklessly linked the Taiwan question with the exercise of collective self-defense, which amounts to a military threat against China and is extremely egregious in nature. Its danger is manifested in four major respects.

First, it exposes that Japan's large-scale military expansion is directed squarely at China, gravely undermining peace and stability in East Asia.

By invoking collective self-defense, Japan seeks to draw the United States into a potential conflict in the Taiwan Strait and jointly obstruct China's reunification by force. This portends the possibility that Japan may once again become a source of war in Asia.

After half a century of colonial rule over Taiwan, Japan now appears, on the occasion of the 80th anniversary of Taiwan's restoration to China, to be reviving ambitions toward the island -- a move that neither the Chinese government nor the Chinese people will ever accept.

Second, Japan's recent statements implying possible military action against China constitute a serious challenge to the postwar international legal framework. This framework was established through foundational documents such as the UN Charter, the Potsdam Proclamation, and the Cairo Declaration.

The Cairo Declaration stipulates that all the territories Japan has stolen from China, including Taiwan, shall be restored to China.

In July 1945, the Potsdam Proclamation jointly issued by China, the United States, and the United Kingdom, calling for Japan's surrender, emphasized that "the terms of the Cairo Declaration shall be carried out."

In September of the same year, Japan, in its Instrument of Surrender, explicitly pledged to faithfully fulfill the obligations laid down in the Potsdam Proclamation.

In the 1972 Sino-Japanese Joint Statement, the Japanese government again undertook to adhere to the position set forth in Article 8 of the Potsdam Proclamation.

By deliberately evading these commitments and instead invoking the illegal and invalid Treaty of San Francisco to fabricate the fallacy that "Taiwan's status remains undetermined," Takaichi is suspected of subverting the postwar international law and order and the political and legal foundations of China-Japan relations.

Third, such rhetoric violates both international law and Japan's domestic law, and has crossed the red line on the Taiwan question.

The UN Charter, the Treaty of Peace and Friendship between China and Japan, and the Constitution of Japan all stipulate the peaceful settlement of international disputes and prohibit the threat or use of force.

Article 98 of the Constitution of Japan further provides that treaties concluded by Japan and established international law shall be faithfully observed.

The Taiwan question, at the core of China's core interests, concerns China's internal affairs. Yet Takaichi has deliberately internationalized the issue and threatened to resort to force, thereby seriously endangering China's national security and peace in East Asia.

Fourth, similar reckless remarks have appeared repeatedly in history, and Japan is showing a dangerous tendency to return to the old path of militarism.

From the Meiji Restoration in 1868 to its defeat and surrender in World War II in 1945, Japan repeatedly used such pretexts as "survival-threatening situation" or "protecting the safety of Japanese nationals overseas" to expand its military and launch wars of aggression, ultimately sliding into militarism.

Today, Japan's renewed invocation of "survival-threatening situation," combined with efforts to revise the "three security documents" including the National Security Strategy, to sharply increase defense spending, to continuously loosen restrictions on arms exports, and even to export lethal weapons, all mark a departure from the postwar path of peaceful development.

Should Japan persist on this path, it risks severely undermining regional and global stability. Confronted with this trend, the international community -- particularly its own citizens -- must maintain vigilance and unequivocally oppose such developments.

(Liu Jiangyong is a professor at the Department of International Relations, Tsinghua University.)