A fight between Japan and China remains the ugliest possible outcome of Japan’s newly-implemented national security policies. Japan’s invasion of China in WWII engendered an inextricable historical feud between the two nations. While Japan may never offer a formal apology for the atrocity, China feels that no compensation from Japan can mitigate the crime. China–Japan relations have been hampered by this incessant problem. Now that Japan and China are pitted against each other in a putative contest for supremacy in Asia, an unleashed Japan may stage a tough match with a rising China. Provocative moves on either side could trigger a showdown. The increased Chinese and Japanese militarization around the Senkaku Islands portends the possibility of such a conflict. Though no shots have been fired (yet) in the region, it is not difficult to imagine how this regional powder keg could be set off by a small miscalculation between the two nations. For example, conflict could be sparked by the sailing of a Chinese vessel within the Senkaku Islands' twelve mile territorial waters or an unsavory interaction between Chinese and Japanese fighter jets in the two nations’ overlapping air defense identification zones. Given each nation’s military capacity and economic power, a war between the world’s number two and three economic powers would be long and costly. Adding fervent Chinese and Japanese nationalism to the mix creates an extremely potent brand of international conflict.

During a 2014 trip to Japan, President Obama made a bold pledge to Prime Minister Shinzo Abe: The United States will protect the Senkaku Islands within the umbrella of the U.S.–Japan security alliance because they are administered by Tokyo. However, in the case of an actual Chinese takeover of the islands, the U.S. commitment to Japanese security could prove extremely problematic. Consider the possible outcomes of U.S. participation in a China–Japan conflict over the Senkaku Islands. After nearly a decade of bloody engagements in the Middle East, how could a future U.S. President convince the American public that the nation ought to support Japan in a war over a number of uninhabited, seemingly meaningless rocks? Even if U.S. leaders were somehow able to convince the populace that the Senkaku Islands dispute threatened U.S. national interests, the brutality of the conflict would surely lead to extensive expenditure of U.S. blood and treasure. On the other hand, how could the United States renege on its security commitment to Japan? There are no good answers to these questions. Clearly, a China–Japan war would place the United States in an ugly foreign policy position.

On June 23, 2015 Japan made its first move in the South China Sea. Its military P3-C Orion surveillance plane flew over a disputed feature between the Philippines and China as part of a Japan-Philippine-U.S. search and rescue exercise. In the meantime, Japan has made it clear that its military will get more involved in this area. While Japanese military assistance can potentially help the United States, it can also exacerbate longstanding territorial contests and fan the flames of unresolved disputes between Japan and China. Japan’s moves stand to make the situation even more contentious.

Japan Unleashed: Immense Potential and Enormous Pitfalls

Since the mid-1990s, the United States has encouraged Japan to act more proactively in security affairs. Both the landmark 1997 U.S.–Japan Defense Guidelines that require Japan to take measures to address security “situations in areas surrounding Japan” (in situational rather than geographic terms) and the U.S.–Japan Security Consultative Committee joint efforts since 2000 that operationalize Japan’s role step by step evidence the United States’ prominent influence in Japanese security operations.

It is clear that the path toward an even stronger U.S.–Japan alliance is dotted with numerous pitfalls. Presently, it appears that Japan’s revolutionary security bills offer the United States many benefits; chiefly, Japan can now serve as a counterbalance against increasingly assertive Chinese behavior in the Asia-Pacific. However, looking ahead to the next several decades, both nations should act carefully within this nascent security arrangement. Japan’s military independence presents numerous opportunities for the creation of regional conflicts that would demand U.S. action. The United States and Japan are walking on a path toward mutual national security gains in one of the world’s most volatile regions, but each nation should tread lightly.

David Lai, Ph.D., is Research Professor of Asian Security Affairs at the Strategic Studies Institute of the U.S. Army War College. Noah Lingwall is an intern at the Strategic Studies Institute and a student at the Schreyer Honors College of Pennsylvania State University. The views expressed in this article are those of the authors and do not necessarily reflect the official policy or position of the U.S. Army War College, the U.S. Army, the Department of Defense or the U.S. Government.

Image: Flickr/Official U.S. Navy