[Update: I recently completed a more extensive analysis on the dispute; that article is available here.]

I’d like to share a couple brief thoughts on the Senkaku/Diaoyu Islands dispute, which has intensified pretty dramatically in recent weeks. The islands together comprise only seven square kilometers and have supported virtually no economic activity other than the collection of guano and bird feathers, but China and Japan both vigorously claim them as their own. This disagreement has been intractable for a variety of reasons. One is the economic stakes—sovereignty over the islands will dictate rights to potentially massive oil and gas deposits under the East China Sea, so there is no financial incentive for conciliation. Another reason is historical animosity—having suffered from Japanese colonialism and militarism during much of the first half of the twentieth century, China is particularly keen on defending against what it perceives to be expansionist Japanese territorial claims. Finally, the dispute is intractable for legal reasons, as I hope to illustrate below.

First some historical background: Chinese sailors reportedly used the islands for a number of purposes for centuries, but Japan formally annexed them in 1895 and then, at the end of World War II, transferred administrative authority to the United States. A 1968 study first raised the possibility of extensive oil and gas resources around the islands. Approximately four years later in 1972, China objected to Japanese sovereignty, and the United States returned the islands to Japanese administration. To demonstrate its control, Japan has since leased the islands to private businessmen, built a weather station and heliport, conducted land surveys, and patrolled the surrounding waters. China has consistently objected that these activities are irrelevant, at least in part because the annexation was illegal and Japan never had sovereignty to begin with.

International law’s indeterminacy seems to have complicated efforts to achieve a resolution. For example, one possible solution would rely upon the doctrine of “acquisitive prescription”—the international law equivalent of adverse possession. This doctrine holds that a state that neglects to contest a claim of sovereignty over a portion of its territory will lose that territory if another state publicly exercises authority over it for a sufficient period of time without interruption. Acquisitive prescription has come up in a variety of comparable situations before, such as Britain’s dispute with Argentina over control of the Falkland Islands. In the Senkaku Islands dispute, the argument would be that even if China had original sovereignty, Japan publicly asserted control through annexation in 1895, and China effectively ceded sovereignty by failing to object to annexation or otherwise assert its authority from 1895 to 1945. The doctrine’s contours, however, are poorly defined. Unlike many domestic adverse-possession doctrines in the United States, for example, international law does not identify the length of time necessary for acquisitive prescription to occur. Thus, while 1895 – 1945 might seem like a long time, there is simply no firm basis for saying whether it is sufficient. The result is that neither side can identify with any objectivity the strength of their legal position. This in turn deters the two sides from consenting to adjudication in the International Court of Justice. The stalemate thus continues.