The Diaoyu Islands, known to the Japanese as the Senkaku, consist of five uninhabited islets and three barren rocks.

The disputed islands are located approximately 170 km southwest of Japan’s Okinawa, the same distance from the northern tip of Taiwan, and 380 km from Wenzhou on the Chinese mainland.

The dispute over the sovereignty of these islands mainly concerns China, including Taiwan, and Japan, but the United States has played an integral role in the dispute from the beginning and will likely continue to be involved.

To summarize the US role in one word, it would be “ambiguous.” But behind the ambiguity - or neutrality in the words of the US government - are its strategic interests, which can be seen from the economic, political, or geographical perspectives. China and Japan, in turn, invoke US rhetoric and actions to strengthen their respective claims.

The dispute dates back to the first Sino-Japanese War in 1894-1895. More modern disagreements are directly related to the redistribution of territories seized by Japan during World War II.

Following the Sino-Japanese War, Japan and the Qing Dynasty government of China signed the Treaty of Shimonoseki, in which China agreed to cede Taiwan, then known as Formosa, to Japan “together with all the islets appertaining or belonging to the said island of Formosa.”

The treaty did not specifically mention the Diaoyu Islands, which led to Japan and China each having a different interpretation of the treaty. China considers the Diaoyu Islands as part of the Chinese territory of Taiwan since ancient times, and sees the treaty as ceding the islands to Japan. Japan argues it formally incorporated the islands into Japanese territory on January 14, 1895.

Since the end of World War II, the US has played an active role in the dispute. The Cairo Declaration issued by Winston Churchill, Franklin Roosevelt and Chiang Kai-shek in December 1943, said “Japan shall be stripped of all the islands in the Pacific which she has seized or occupied since the beginning of the first World War in 1914, and that all the territories Japan has stolen from the Chinese, such as Manchuria, Formosa, and The Pescadores, shall be restored to the Republic of China.”

Furthermore, Article 8 of the Potsdam Declaration states “The terms of the Cairo Declaration shall be carried out and Japanese sovereignty shall be limited to the islands of Honshu, Hokkaido, Kyushu, Shikoku and such minor islands as we determine.”

China argues that the intent of these two Allied declarations was to restore to China territories taken from it by Japan through military aggression, and thus Beijing considers that the islets should have been returned to China.

In October 1945, when Japan relinquished authority over Taiwan, it did not specifically mention the Diaoyu. In addition, when the government of the Republic of China normalized diplomatic relations with Japan in 1952, in the Treaty of Peace between Japan and the Republic of China, the subject of the islands was not raised by either side.

US administration of the islets began in 1953 as a result of the 1951 Treaty of Peace with Japan, though neither the Guomindang government on Taiwan nor the People’s Republic of China government was invited to the conference that crafted the treaty.

Article 3 gave the US sole powers of administration of “Nansei Shoto south of 29 north latitude (including the Ryukyu and the Daito Islands)….”

In 1953, the US Civil Administration of the Ryukyus issued US Civil Administration of the Ryukyus Proclamation 27, which defined the boundaries of “Nansei Shoto [the southwestern islands] south of 29 degrees north latitude” to include the Senkakus.

When the US started to discuss with Japan the transfer of the administrative rights over Okinawa to Tokyo, leading to The Okinawa Reversion Treaty - which was signed on June 17, 1971 and entered into force on May 15, 1972), Taibei urged the US in September 1970 not to include the Senkaku Islands, and to keep the sovereignty issue open.

As a result, in presenting the Okinawa Reversion Treaty to the US Senate for ratification, the State Department asserted that the US took a neutral position with regard to the competing Japanese and Chinese claims to the islands, despite the return of the islands to Japanese administration. Department officials asserted that reversion of administrative rights to Japan did not prejudice any claims to the islands.

When asked by the Chairman of the Senate Foreign Relations Committee how the Okinawa Reversion Treaty would affect the determination of sovereignty over the Diaoyu Islands, Secretary of State William Rogers answered that "this treaty does not affect the legal status of those islands at all."

Then, in his letter of October 20, 1971, Acting Assistant Legal Adviser Robert Starr stated: “The Governments of the Republic of China and Japan are in disagreement as to sovereignty over the Senkaku Islands. You should know as well that the People's Republic of China has also claimed sovereignty over the islands. The United States believes that a return of administrative rights over those islands to Japan, from which the rights were received, can in no way prejudice any underlying claims. The United States cannot add to the legal rights Japan possessed before it transferred administration of the islands to us, nor can the United States, by giving back what it received, diminish the rights of other claimants. The United States has made no claim to the Senkaku Islands and considers that any conflicting claims to the islands are a matter for resolution by the parties concerned.”

Successive US administrations have restated this position of neutrality regarding the claims. This stance is somewhat ambiguous, however, and complicates the dispute concerning the 1960 Treaty of Mutual Cooperation and Security between the US and Japan.

According to Article 5 of the treaty, "Each Party recognizes that an armed attack against either Party in the territories under the administration of Japan would be dangerous to its own peace and safety and declares that it would act to meet the common danger in accordance with its constitutional provisions and processes."

In short, this means the US is technically bound to defend Japan's claim over the islands in case of armed confrontation between China and Japan.

Scholars have different opinions about the development of the territorial dispute and the possible role that the US can play.

Eric Posner, a professor at the University of Chicago Law School, wrote for the news website Slate that “…if World War III takes place anytime soon, this is where it will start—implausible as that may sound.”

Dr. Habib Siddiqui predicted in a letter to the Asian Tribune that “In the initial stage although the USA may not take a side (simply because its long term strategic objectives are better served through mutual weakening of both the parties to the dispute through conventional warfare), as the war drags on the USA will take the side of Japan.”

Some US scholars have noted that there is no automatic commitment on the part of the US to defend the islands since any of its actions would have to be taken "in accordance with its constitutional provisions and processes."

On September 16, 1996, The New York Times reported that Walter Mondale, former US ambassador to Japan, indicated that "the United States takes no position on who owns the island... American forces would not be compelled by the treaty to intervene in a dispute over them."

And Tetsuo Kotani, a Research Fellow at the Japan Institute of International Affairs (JIIA), said China is testing the credibility of the US-Japan alliance and the outcome of the current struggle over the Senkakus will have significant implications for the future of the Asia-Pacific.

China and Japan have formally contested any claims to the Diaoyu Islands for a long time – but without using force.

M. Taylor Fravel, associate professor of Political Science and member of the Security Studies Program at MIT, suggested the absence of armed conflict or even tense military confrontations is nothing short of remarkable. Fravel also said that active dispute management by both China and Japan has helped limit the potential for escalation.

Chinese observers believe the US stance on the Sino-Japan territory dispute is changing from strategic vagueness to strategic clarity, signaling open support for Japan.

Lu Jinghua, an assistant research fellow at the Center on China-America Defense Relations at the Academy of Military Science for the People’s Liberation Army, wrote that the US “pivot” towards the Asia Pacific region provides the background for the US to further deepen its military cooperation with Japan and bolster its ally in confronting China.

The escalation of Japan-China tension is not in US interests. The US obviously needs Japan as its most important ally in East Asia, but it also needs China, not only for economic and trade reasons but also due to global and regional security issues.

Therefore, the potential negative impact of Shinzo Abe's nationalistic behavior and his revisionist views on Japan's wartime past should also be of concern to the US.

Note:

This essay is mainly based on public media reports and also on the following:

Explaining Stability in the Senkaku (Diaoyu) Islands Dispute, M. Taylor Fravel

The Senkaku/Diaoyu Islands territorial dispute between Japan and China, Reinhard Drifte

Senkaku (Diaoyu/Diaoyutai) Islands Dispute: U.S. Treaty Obligations, Mark E. Manyin