Under their 1960 Treaty of Mutual Cooperation, the United States and Japan are military allies. Additionally, Japan’s post-war constitution restricts its ability to wage war, committing it to pacifism and the use of a limited military for the purposes of self-defense exclusively. To complement its limited self-defense capability, Japan relies on a robust United States military presence within its territory to ensure its broader security. For the longest time, numerous officials on both sides described the underlying military and strategic dynamics of this partnership as that of a “spear and shield.” The United States’ formidable offensive capabilities were the “spear” to be paired with Japan’s “shield.” After all, Japan, with its aptly named Self-Defense Forces, could hardly aspire to much more given the circumstances.
The “spear and shield” metaphor is to be contrasted with earlier characterizations of Japan’s post-war defense posture as that of a hedgehog — a meek rodent with a nonthreatening bite, but protected from every angle by its spines. In the 1970s, the Ground Self-Defense Forces spoke in favor of a “hedgehog defense” strategy, calling for Japan to hunker down with the bare minimum required for self-defense. It wasn’t until U.S. President Ronald Reagan and Japanese Prime Minister Zenko Suzuki’s defense consultations in the early 1980s that the seeds of the contemporary “sword and shield” balance was set. As Glenn D. Hook remarks, the shift in metaphor was significant: “The purely defensive image of the hedgehog is thus replaced with an image of both defense (Japan) and offense (United States).” Later in the 1980s, Japanese Prime Minister Yasuhiro Nakasone referred to Japan as an “unsinkable aircraft carrier” — a controversial metaphor considering that was precisely what U.S. forces on the eastern front called Pacific atolls and islands during the campaign against Imperial Japan. In the context of the Cold War, an unsinkable U.S. carrier off the Soviet Union’s eastern frontier was a provocative image.
Decades later, we are witnessing change in Japan’s defense posture. It’s no secret that the current Japanese administration is keen to recast Japan’s role as a security actor in East Asia. Prime Minister Shinzo Abe has framed his vision for Japan’s military as an instrument of “proactive pacifism” in the Asia-Pacific. To this end, his government fast-tracked the reinterpretation of the Japanese constitution’s long-standing ban on collective self defense, drafted a new national security council to implement a new national defense posture, and worked to set up defense deals the world over. Additionally, the United States and Japan are currently in the process of overhauling their defense guidelines. At the core of all these initiatives is a deeply held impulse by the current administration that Japan ought to be a “normal” military power.
The U.S.-Japan interim report on defense guidelines released in early October highlighted that the most fundamental shift in the alliance will be its “global nature” — something largely made possible by the Abe administration’s moves on collective self-defense earlier in the year. Additionally, the report specifies that the final guidelines (to be released by year’s end) will focus on a “whole-of-government Alliance approach” and “cooperation with other regional partners.” The latter point almost certainly includes India and Australia, and may even include South Korea.
The defense guideline overhaul largely concerns the “software” aspect of U.S.-Japan military cooperation. There is the more complicated question of the “hardware” side of matters. In reacting to a rising and increasingly assertive China, Japan is making important investments in next-generation defense technology. The Izumo-class helicopter carriers (the largest Japanese naval ships since the Second World War), advanced Soryu-class submarines, and even talk of an indigenous stealth fighter highlight Tokyo’s evolving strategy. As a report in Defense News noted recently, driving Japan’s development and investment in these systems is China’s anti-access/area-denial (A2/AD) strategy. Additionally, Japan is investing in ballistic missile defense (BMD) Aegis batteries and is looking to double the number of BMD destroyers in its fleets by 2018.
Amid all this, it’s worth reiterating that none of this means that Japan is “remilitarizing” — especially in the sense that Chinese nationalists fear. Japan is already one of the more capable and prominent military powers in the region and has been for years. While on the surface these “hardware” changes appear to signal a new era for the Japanese military, the truth of the matter is that even under the nationalist Abe administration, Japan’s hands are tied in important ways. Additionally, given that this summer’s resolution on collective self-defense proved unpopular with the Japanese public, Abe’s Liberal Democratic Party (LDP) will likely lack the political capital in the short term to make any more radical changes to Japan’s defense posture. Furthermore, given recent reports that the Abe administration could be seeking to forge a stable detente with China over the ever more pressing issue of the Senkaku/Diaoyu territorial dispute, it may be some time before we see Japan and the United States make good on their commitment for a more global alliance.
Overall, the new U.S.-Japan defense guidelines don’t fundamentally alter the “spear and shield” dynamics of the U.S.-Japan alliance. While many in the United States would undoubtedly like to see Japan shoulder a greater part of the burden in a time when defense budgets are growing tight and while the Abe government might reciprocate this desire, the established rubric of bilateral military cooperation will resist fundamental transformation. Despite the more granular changes in the U.S.-Japan alliance, the ultimate guarantee of Japanese security — the U.S. nuclear umbrella — persists. As long as the United States’ “spear” remains sharp and credible in the Asia-Pacific, there is little reason for concern that Japan could behave unpredictably. True military normalization for Tokyo will only emerge after that assumption no longer holds.