	Introduction1

Periodically, tensions flare up between Japan and China over a small group of Japanese-administered islands located in the East China Sea. Japan, China, and Taiwan all claim sovereignty over the islands, known as the Senkaku-shoto in Japan, the Diaoyu Dao in China, and the Diaoyutai Lieyu in Taiwan. Some geologists believe that the waters surrounding them may be rich in oil and natural gas deposits. Each time a crisis has erupted over the Senkakus (Diaoyu/Diaoyutai), questions have arisen concerning the U.S. relationship to the islands. This report focuses on that issue, which has four elements: 
1. U.S. administration of the islands from 1953 to 1971, when the United States occupied Okinawa; 2. the application to the Senkakus (Diaoyu/Diaoyutai) of the 1971 "Treaty Between Japan and the United States of America Concerning the Ryukyu Islands and the Daito Islands"—commonly known as the Okinawa Reversion Treaty, which was approved by the Senate in 1971 and entered into force the following year (the Daito Islands lie to the east of Okinawa); 3. the U.S. view on the claims of the disputants; and 4. the relationship of the 1960 U.S.-Japan Security Treaty to the islands. Administrations have restated this position of neutrality regarding the sovereignty claims, particularly during periods when tensions have flared, as in 1996, 2010, and 2012. The U.S.-Japan Security Treaty and the Islands

Article 5 of the 1960 U.S.-Japan Security Treaty stipulates that 
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. Then-Deputy Secretary of Defense David Packard, in his testimony, stressed that Japan would assume the "primary responsibility" for the defense of the treaty area but that the Security Treaty was applicable. China's increase in patrols around the Senkakus (Diaoyu/Diaoyutai) since the fall of 2012 appears to many to be an attempt to demonstrate that Beijing has a degree of administrative control over the disputed territory, thereby exploiting the U.S. distinction between sovereignty and administrative control. Thereafter, some observers, seeking to avoid a situation where the United States inadvertently encourages more assertive Chinese actions, called on Obama Administration officials to stop using the word "neutral" in describing the U.S. position on the issue and also to publicly declare that unilateral actions by China (or Taiwan) will not affect the U.S. judgment that the territory is controlled by Japan. In its own attempt to address this perceived gap, Congress inserted in the FY2013 National Defense Authorization Act ( H.R. 4310 , P.L. 112-239 ) a resolution stating, among other items, that "the unilateral action of a third party will not affect the United States' acknowledgment of the administration of Japan over the Senkaku Islands," language that since 2012 has reappeared in a number of bills and resolutions concerning U.S. interests in the East China Sea. Speaking to the press with Prime Minister Shinzo Abe in Tokyo in April 2014, President Obama underscored the U.S. commitment in what are believed to be the first public remarks by a U.S. President stating the U.S. position on the Senkakus (Diaoyu/Diaoyutai) dispute. In February 2017, during his first joint press appearance as President with Prime Minister Shinzo Abe, President Donald Trump stated that "we are committed to the security of Japan and all areas under its administrative control.... " A joint statement issued by the two governments during their summit said that the two leaders "affirmed that Article V of the U.S.-Japan Treaty of Mutual Cooperation and Security covers the Senkaku Islands. They oppose any unilateral action that seeks to undermine Japan's administration of these islands." The expanded U.S. rhetorical support for Japan on the dispute has been accompanied by increasing bilateral diplomatic coordination on responding to China's increased assertiveness in the South China Sea, as well as increased bilateral security cooperation to boost Japan's maritime and island defenses.
Since the mid-1990s, and particularly since 2012, tensions have spiked between Japan and China over the disputed Senkaku (Diaoyu/Diaoyutai) islands in the East China Sea. These flare-ups run the risk of involving the United States in an armed conflict in the region. Japan administers the eight small, uninhabited features, the largest of which is roughly 1.5 square miles. Some geologists believe the features sit near significant oil and natural gas deposits. China, as well as Taiwan, contests Japanese claims of sovereignty over the islands, which Japan calls the Senkaku-shoto, China calls the Diaoyu Dao, and Taiwan calls the Diaoyutai Lieyu. Although the disputed territory commonly is referred to as "islands," it is unclear if any of the features would meet the definition of "island" under international law.
U.S. Administrations going back at least to the Nixon Administration have stated that the United States takes no position on the question of who has sovereignty over the Senkakus (Diaoyu/Diaoyutai). It also has been U.S. policy since 1972, however, that the 1960 U.S.-Japan Security Treaty covers the islands. The treaty states that the United States is committed to "meet the common danger" of an armed attack on "the territories under the Administration of Japan," and Japan administers the Senkakus (Diaoyu/Diaoyutai). In return for U.S. security commitments, Japan grants the United States the right to station U.S. troops—which currently number around 50,000—at dozens of bases throughout the Japanese archipelago. Although it is commonly understood that Japan will assume the primary responsibility for the defense of the treaty area, in the event of a significant armed conflict with either China or Taiwan, most Japanese likely would expect that the United States would honor its treaty obligations.
Since 2012, without challenging the U.S. government's position of neutrality over who has sovereignty over the islands, Congress nevertheless has expanded rhetorical support for Japan on the dispute. Congress inserted in the FY2013 National Defense Authorization Act (H.R. 4310/P.L. 112-239) a resolution stating, among other items, that "the unilateral action of a third party will not affect the United States' acknowledgment of the administration of Japan over the Senkaku Islands." Following Congress's statement, Obama Administration officials began using similar language, also without changing U.S. neutrality on the sovereignty question. Most prominently, in April 2014, President Obama reiterated that Article 5 of the U.S.-Japan Security Treaty covers the islands and that "we do not believe that [the Senkakus' status] ... should be subject to change unilaterally." This is believed to be the first time a U.S. President publicly stated the U.S. position on the dispute.
In February 2017, during his first joint press appearance as President with Prime Minister Shinzo Abe, President Donald Trump stated that "we are committed to the security of Japan and all areas under its administrative control.... " A joint statement issued by the two governments during their summit said that the two leaders "affirmed that Article V of the U.S.-Japan Treaty of Mutual Cooperation and Security covers the Senkaku Islands. They oppose any unilateral action that seeks to undermine Japan's administration of these islands."
The expanded U.S. rhetorical support for Japan has been a reaction to China's increasing patrols around the Senkakus (Diaoyu/Diaoyutai) beginning in the fall of 2012, moves that appear to many to be an attempt to exploit the U.S. distinction between sovereignty and administrative control by demonstrating that Beijing has a degree of administrative control over the islands. In a further effort to deter Chinese actions, the United States has increased its support for Japan's efforts to boost its maritime and island defenses.
Each time tensions over the territorial dispute have flared, questions have arisen concerning the U.S. legal relationship to the islands. This report focuses on that issue.