Long fettered by Article 9 of its post-WWII constitution that renounces war as a sovereign right and prohibits the maintenance of military forces, Japan is now poised to unleash its military potential both at home and abroad. The May 14 endorsement of two key defense bills (the international peace support bill and the peace and security legislation development bill) by Japan’s Cabinet signals another big step in this direction. Historically, Japan’s constitution has barred its Self-Defense Forces (SDF) from entering overseas military engagements. The international peace support bill includes the right to exercise collective self-defense, which allows the SDF to assist a friendly nation, first and foremost, the United States, and then other allies and partners, when they are under attack. The peace and security legislation development bill streamlines the process by which Japan can provide logistical support to foreign military forces. Previous constitutional provisions required parliamentary approval each time that the SDF wished to engage in a multinational military operation. This new bill provides a single law under which Japan can assist its allies around the globe.

Japan has good reason to overhaul its postwar military policy. Currently, it faces a host of threats that could require proactive and vigorous military response. North Korea’s pugnacious behavior and growing capability to threaten Japan has been a longstanding concern. China’s recently escalated contest with Japan over the Senkaku Islands and a whole array of other unresolved issues introducing a menacing element into the already precarious relations between the two big Asian nations.

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Japanese Prime Minister Shinzo Abe has announced that these landmark security bills will take effect over the summer. Japan’s new military posture, which is reflected in the updated U.S.–Japan defense cooperation guidelines (released in April 2015), could radically alter both U.S.–Japan relations and East Asian military relations. As the United States maps out Japan’s future defense trajectory, it ought to take note of all of its implications: the good, the bad, and the ugly.

The Good: Increased U.S.–Japanese Cooperation                      

The current U.S.–Japan military partnership is strikingly unequal. The U.S.–Japan mutual defense treaty is not “mutual” at all—Japan is not expected to (by the United States) and cannot (by Japan’s constitutional restrictions) come to the United States’ defense. While Japan maintains imposing Self-Defense Forces and hosts U.S. military bases, the United States bears the immense task of defending Japan from foreign threats. In an April 2015 interview with the Sasakawa Peace Foundation USA (a Washington, D.C.–based U.S.–Japan relations think tank), Admiral Dennis Blair, former Commander of the U.S. Pacific Command, characterized the absurdity of Japan’s previous military restrictions by stating, “Until now, if North Korea shot a missile and Japan’s missile destroyer were in a maritime domain and could shoot it down, the commander would say, ‘The target is the United States, not Japan.’”

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Allowing Japan greater latitude to employ its SDF can serve U.S. interests while easing the United States’ hefty military burden. Consider the example of a crisis in Northeast Asia or the South China Sea. As China’s territorial ambitions in the South China Sea ratchet up fear amongst Southeast Asian nations, a single political or military misstep could send the region into disarray. In the event of such a military flare-up, the United States may require extensive logistical support to mount a proper response. Japan’s SDF can now provide the United States with the intelligence and military assistance necessary to handle a delicate situation in the Asia-Pacific. According to Admiral Blair, this assistance could take the form of missile defense and minesweeping in key ports. The SDF’s newly-acquired ability to lend support to its allies will also benefit U.S commercial (as well as military) interests by bolstering freedom of navigation. Now that Japan’s armed forces are permitted to take part in foreign military operations, Japan can credibly help to defend freedom of navigation alongside the United States.

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As some U.S. policymakers look at China’s rise with increasing trepidation, Japan’s new defense bills should provide a comforting counterbalance in the Asia-Pacific. The introduction of a new and formidable military presence in the region significantly complicates China’s defense calculus. With the new defense bills, China must worry about Japan as a separate military entity from the United States. The South China Sea dispute has not yet escalated to a level where military forces are required to quell the conflict. It appears that administrative and political means still offer the best chance to resolve the contentious territorial disputes. Still, even in this war of words, Japan’s new military capabilities back up words with firepower and provide balance and deterrence against Chinese assertiveness in the Asia-Pacific.

The Bad: An Unknown Security Future in the Asia-Pacific

The rise of Japan’s SDF interrupts a decades-long trend of U.S. military dominance in the Asia-Pacific. There is nothing inherently unwise about the United States ceding some military influence to the Japanese. Still, from a U.S. policymaking perspective, the rise of Japan’s newly-empowered SDF will mean that the United States will not be able to call all of the shots on behalf of Japan. The United States must understand that, as a militarily-independent nation, Japan may choose to act in ways that clash with U.S. policy interests. For example, Japanese Prime Minister Shinzo Abe's doctrine of "active pacifism" and the tenets of collective self-defense could allow Japan to strengthen its ties with Australia, South Korea, the Philippines, Vietnam, and other regional players. This could lead to a new regional security arrangement in which a multipolar web of alliances supplants the traditional, U.S.–led “hub-and-spoke network” of alliances.

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It is also possible that Japan’s apparent commitment to providing allies with military assistance could lead to a profound “perceptions gap” between the United States and Japan. The new defense bills lead the United States to believe that the SDF will be willing to provide logistical support to U.S. forces in risky situations. However, as Japan faces deflation and a dwindling GDP, it is possible that Japanese enthusiasm for foreign assistance will soon wane. In a recent address regarding Japan’s economic situation, Prime Minister Shinzo Abe declared, “Japan cannot drastically increase its defense spending, but we can still ensure that the Japan-U.S. security alliance will function better.” Abe’s words attempt to strike a precarious balance between addressing domestic needs and upholding international commitments to the United States. In the event of prolonged economic stagnation or domestic unrest, Japan could falter in its promise to assist global allies. Therefore, while Japan appears committed to contributing toward U.S.–Japan joint military ventures, there is reason to suspect that Japanese contributions will not meet U.S. expectations.

Moreover, as Japan modernizes its military and begins to play a larger role in the Asia-Pacific security environment, the United States must consider the possibility of a nuclear Japan. The United States’ “nuclear umbrella” has sheltered Japan and eliminated the need for Japan to develop its own nuclear program thus far. As Japan looks toward potential threats stemming from its hostile neighbors (such as North Korea, China, and Russia) it is conceivable that its leaders may feel compelled to establish the nation’s nuclear presence. According to a senior Japanese government official, Japan has possessed the ability to build nuclear weapons since it constructed a plutonium breeder reactor and a uranium enrichment plant thirty years ago. Some of the more hawkish factions within Japan’s government boast that their nation could practically develop a nuclear weapon “overnight.” How should the United States handle a nuclear Japan? How will the introduction of a nuclear Japan alter the Asia-Pacific security landscape? These contingencies could potentially upset an already delicate regional power balance.

The Ugly: War with China and U.S. Response

Reinvigorated Japanese influence in the Asia-Pacific could lead its policymakers to approve risky military ventures. The author of a May 2015 editorial in The Asahi Shimbun fears that Japan could end up saddling itself with the strain of serving as a guarantor for regional security. Once Japan takes the first step toward military operations in armed conflicts, it could quickly become entangled in small flashpoints in the Asia-Pacific. Some Japanese commentators cite concerning loopholes in the new security bills as an indication that Japan’s security reforms could lead the nation down a radical path. According to commentators, those loopholes could afford Prime Minister Shinzo Abe and the LDP-Komeito coalition enough leeway to push Japan into more expansive military commitments than originally envisioned by the bills’ supporters. 

Even though Japan has effectively ended its longstanding reliance upon the United States military, the United States still must uphold its commitment to support Japanese national security interests. Therefore, it is possible that Japan’s actions could drag the United States into regional conflicts for which the United States has neither the time nor money.

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