During a telephone conversation between senior defense officials last week, Washington reiterated its position that the Senkaku Islands fall under the United States’ scope of alliance commitments to Japan.

This came just a few days after President-elect Joe Biden also reaffirmed this pledge in his first telephone call with Prime Minister Yoshihide Suga. Reports of this have rekindled a long-standing debate on the utility of such statements of commitment.

The Senkaku Islands are the source of territorial disputes between Japan, China, and Taiwan. The five uninhabited islands in the East China Sea are themselves unremarkable, but the maritime area around them is important both for natural resources and access between mainland Asia and the broader Pacific Ocean.

Disputes over the territory came to a head in 2012 when the Japanese government purchased the islands from private landowners, effectively nationalizing the Senkakus. Since that time, China has engaged in a slow but steady campaign to change the status quo in administration of the islands so that the country may eventually vie for unilateral control.

Washington has stated and reiterated its position that the Senkakus fall under U.S.-Japan Mutual Security Treaty obligations. The first statement of commitment came in 2010 when then-Secretary of State Hillary Clinton asserted during a joint news conference that the islands were covered under the treaty. The first presidential-level assertion came in 2014 when President Barack Obama stated it. Senior U.S. officials have reaffirmed this point in joint statements and communiques since.

Still, many question the nature and validity of this constantly renewed commitment. Is the United States really ready to get dragged into a war over rocks in the middle of the ocean? Will any adversary actually buy the notion that Americans will defend the Senkakus? If the U.S. has already made a commitment, why is the Japanese government so keen for its U.S. ally to renew it time and again?

The simplest answer is that the United States and Japan are allies and that it is only natural for them to display solidarity in the face of a Chinese government that is consistently threatening the rules-based international order. But alliance management, as with most things in life, is almost never simple.

Questions like those surrounding the Senkakus are useful for understanding some of the fundamental principles of defensive alliances, especially the two basic fears associated with military pacts. The first fear is that of abandonment; that is, the fear that an ally will fail to meet its end of the bargain and abandon its obligations in a time of need. The second is that of entrapment — that a security commitment to an ally will draw one into an unwanted war.

These fears exist in any alliance relationship, but the Senkaku Islands issue illustrates those fears well. For the Japanese side, many have made the case that Tokyo has at least a modicum of fear that Washington will not take action to support the defense of the Senkakus. This would explain the government’s consistent desire to renew U.S. commitments in joint statements and senior level discussions.

For the U.S. side, the fear of entrapment can influence behavior in one of two ways. First would be reticence to offer explicit commitments. Policy advisors arguing for such caution would assert that extending U.S. commitment is more likely to embolden the Japanese government; in other words, they believe that Japan might take unnecessary risks in responses to any would-be challengers to the Senkakus.

The second way would be a desire for extreme clarity in expressions of commitment. In this case, policy advisors would argue that failure to offer a clear commitment could alienate Japan, which might cause an unwanted, unilateral response to a Senkaku Islands crisis rather than a coordinated alliance decision. Those individuals would also argue that failure to offer a commitment would embolden adversaries, which could then lead to escalation that would eventually entrap the United States in conflict anyway.

To mitigate fears of abandonment and entrapment, allies tend to be explicit in their alliance designs and their stated commitments. Indeed, this gets at the core of why countries sign alliance treaties in the first place: treaties and associated commitments clarify rights and obligations to each other, and this helps manage expectations.

In the case of the Senkakus, these consistent statements of commitment reduce the fears of abandonment and entrapment and allow the allies to focus their energies on coordinated activities.

Treaties and commitments are also important because they signal to adversaries the potential costs of picking a fight with one of the allies. Absent those signals, would-be adversaries could miscalculate how the allies might respond to certain actions.

It is critical to understand that lack of information or enough bad information can contribute to conflict. In the case of alliances, broadcasting commitments eliminates some of those information problems.

One of the cases that many will point to about the folly of failing to provide clear commitments is the Korean War. On Jan. 12, 1950, Secretary of State Dean Acheson declared the so-called “Acheson Line,” identifying the territories that fell under U.S. defense commitments.

This declaration was meant to have a stabilizing effect in East Asia, but there was a major problem: South Korea was clearly left out of the areas covered under the Acheson Line. Many argue this policy misstep is what emboldened the communist bloc enough to convince Josef Stalin to give Kim Il Sung the greenlight to invade South Korea.

This example is especially salient for the Japanese, who are loath to allow any seams that could be exploited by a Chinese government that already has designs for the Senkakus. Hence, the Japanese government has been keen to ensure that its U.S. ally clarifies its treaty commitments as a clear signal to the Chinese of the potential costs of military action associated with the islands.

Has it worked though? The deterrent effect of the Japan-U.S. alliance has not stopped Chinese activity in vying for control of the Senkakus, but one can make a strong case that it has changed the nature of it. Rather than using overt military capabilities as one may observe in the South China Sea, the Chinese have focused on employing its coast guard and fishing fleets around the Senkakus. While this is still a cause for concern, it has lowered the level of incidents that could potentially occur, at least for the time being.

Thus, whatever the debates may be, there seems to be utility in the U.S. and Japanese governments making their allied position abundantly clear. The allies recognized the flashpoint for crisis that the Senkakus represent and have used statements of commitment to signal an important message: Starting a fight in the Senkakus is against the best interests of all parties involved. This in turn has influenced Chinese behavior.

Although a mere statement is not going to stop Chinese ambitions in the East China Sea altogether, the renewed commitments help eliminate perceived gaps in the alliance and warn off Chinese military action that could potentially lead to consequential miscalculation. Considering the positive impact this has on regional peace and stability, tacking on a few redundant statements in phone calls and joint communiques seems like a small price to pay.

Dr. Michael MacArthur Bosack is the special adviser for government relations at the Yokosuka Council on Asia-Pacific Studies. He previously served in the Japanese government as a Mansfield fellow.

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