Forged in the wake of World War II, the U.S.-Japan security alliance has served as one of the region's most important military relationships and as an anchor of the U.S. security role in Asia. Revised in 1960, the Treaty of Mutual Cooperation and Security grants the United States the right to military bases on the archipelago in exchange for a U.S. pledge to defend Japan in the event of an attack. The partnership has endured several geopolitical transitions, rooting its framework in the postwar security environment and expanding in the aftermath of the Cold War with the rise of China and a nuclearizing North Korea. Cooperation during the Gulf and Iraq wars and the March 2011 Tohoku earthquake reaffirmed the strength of the alliance, but challenges remain. The U.S. military presence on Okinawa, North Korea's nuclearization, territorial disputes with China, and Japan's recent push to upgrade its defense preparedness have all challenged the alliance's resilience as the Obama administration considers the direction of its strategic pivot to the Asia-Pacific region.
U.S.-Japan Defense Treaty
Signed in 1951 alongside the Treaty of San Francisco that ended World War II, the original U.S.-Japan Mutual Security Treaty was a ten-year, renewable military agreement that outlined a security arrangement for Japan in light of its pacifist constitution. U.S. forces would remain on Japanese soil after Japan regained sovereignty. This early security pact with Washington dovetailed with the Yoshida Doctrine [PDF]—a grand strategy for postwar Japan laid out by then prime minister Yoshida Shigeru that saw Japan rely on the United States for its security needs so the country could focus on its own economic recovery.
At the time, the United States was keen on keeping its presence in Japan and using the alliance to bolster its strategic presence in East Asia. It faced a divided Korean peninsula in the wake of the Korean War, and a Cold War climate in which Chinese and Soviet militaries were expanding their breadth and capabilities. Against this security backdrop, Yoshida's government created the Self-Defense Force (SDF) in 1954, despite strong domestic objections based on Article Nine of the postwar constitution, which eschews the maintenance of military forces or the use of those forces to settle international disputes.
"With the ebb and flow of what's going on in the region, these are two countries that are highly incentivized to make this work." —Jennifer Lind
Japan had assumed a minimal military role within the alliance in the early post–World War II years, interpreting the constitution to prevent the overseas deployment of Japanese troops. The value of the security pact to Washington, however, was the use of Japanese bases that allowed for the forward deployment of U.S. forces in Asia. The U.S. military used Japanese bases for combat operations during the Vietnam War, which drew vehement opposition in Japan and triggered fears of entrapment within the security alliance. In 1967, then prime minister Sato Eisaku enacted the Three Non-Nuclear Principles—no possession, production, or introduction—in part to allay concerns that the presence of nuclear arms on U.S. bases in Japan would expose the country to attacks. Since then, Japan has relied on the U.S. nuclear umbrella for extended deterrence.
In the 1970s, Japan began to increase its role within the alliance, while the United States disengaged from the Vietnam War. In 1976, Japan put out a National Defense Program Outline, its first comprehensive postwar defense strategy. Two years later, the 1978 Guidelines for Defense Cooperation it signed with the United States established a framework for the roles between the two militaries for Japan's defense. Washington and Tokyo began joint studies on interoperability and, most notably, launched joint training and exercises. The 1990–91 Gulf War prompted a new debate in Japan about SDF participation in UN-sponsored peacekeeping operations. A new law was adopted stipulating the conditions for SDF deployment abroad in UN peacekeeping operations, and the first SDF unit was sent to Cambodia.
North Korea and the Nuclear Question
The fall of the Soviet Union marked a drastic shift in the regional security environment, with an ascendant China emerging alongside a nuclearizing North Korea. Pyongyang's fast-developing ballistic missile and nuclear program began to pose an existential military threat that exposed limitations [PDF] in the alliance.
Such fissures arose during the North Korean missile crisis of the mid-1990s. In May 1993, North Korea launched a Nodong missile into the Sea of Japan and withdrew from the Nuclear Nonproliferation Treaty to begin developing nuclear weapons material. The United States, keen on preserving stability in the region, found that Japan's constitutional limitations and the 1978 guidelines hindered its military preparations for a contingency on the peninsula. Exacerbating regional tensions was the 1996 Taiwan Strait Missile Crisis [PDF], during which two U.S. aircraft carriers flew over the strait in response to Chinese missile tests.
In response to the burgeoning security instability, the alliance adopted the new U.S.-Japan Defense Guidelines in September 1997 that expanded the allowance of Japan's military operations from its home islands to "surrounding areas"—a move some perceived as Japan taking greater responsibility for its own defense. "These crises reminded us in Washington and Tokyo that we weren't really quite out of the Cold War in Northeast Asia," says CFR Senior Fellow Sheila Smith. "The flash points [in the 1990s] continued to challenge the alliance and its response."
Tokyo and Washington consolidated their development of ballistic missile defense programs after North Korea fired another missile over Japanese airspace in mid-1998. A 2006 nuclear test and more recent provocations from North Korea ignited a debate in Japan about the acquisition of nuclear weapons for its self-defense. In 2008, the Bush administration removed North Korea from its list of state sponsors of terrorism in exchange for concessions on its nuclear program. The shift toward negotiations with Pyongyang triggered fears in Tokyo that Washington could accept a nuclear North Korea, diminishing the U.S. security guarantee for Japan.
China and the Diaoyu/Senkaku Islands Dispute
As the United States makes its "pivot" to the Asia-Pacific region, China's rapid rise has been at the center of alliance concerns. In 2010, it surpassed Japan as the world's second-largest economy, and its growing assertiveness in the East and South China Seas have prompted worries about its regional ambitions. The escalating territorial dispute over the Diaoyu/Senkaku Islands, a cluster of uninhabited islets in the East China Sea, has riled bilateral relations and led many observers to fear a military clash in those waters. Although Washington has maintained that it does not take a stance on the islands' sovereignty status, it considers them to be under Japanese administration and thus covered by the security treaty.
"Here's an area where we see a really fascinating transformation in the alliance dynamic, where there's been a complete swing in the fear of entrapment," says Jennifer Lind, associate professor of government at Dartmouth College. "For sixty years, the Japanese were afraid that we would drag them into a war. Now, we have the opposite problem in the Diaoyu/Senkakus."
Though territorial skirmishes had flared in the area for years, Sino-Japanese relations hit a nadir in the summer of 2012, when Chinese activists landed on the disputed islands, triggering Japanese activists to reciprocate. Tokyo's government, led by then prime minister Yoshihiko Noda, proceeded to purchase three of the five islands from a private landowner for two billion yen in September, despite State Department warnings. The move ignited a wave of anti-Japanese protests across China that included a monthlong boycott of Japanese goods, bruising Japanese exports. The heightened tensions led the Japanese Coast Guard to bolster its surveillance of the waters and renew calls for stationing permanent structures and personnel on the islands.
Tensions flared again in November 2013, when China's Ministry of Defense announced the creation of an East China Sea Air Defense Identification Zone. The protocol requires all noncommercial air traffic to submit flight plans before entering the area, which encompasses most of the East China Sea and includes the Diaoyu/Senkaku Islands. In response, U.S. secretary of defense Chuck Hagel reaffirmed that the U.S.-Japan Mutual Defense Treaty covered the disputed islands, and Vice President Joe Biden, on a week-long trip to the region, expressed deep concern regarding China's assertions. Further underscoring U.S. support for Japan's security, President Obama backed Tokyo's administration of the islands during an April 2014 visit to the region. "What is a consistent part of the alliance is that the treaty covers all territories administered by Japan," he said.
Given the impasse between Beijing and Tokyo, many have called on the United States to increase its role as a mediator in the escalation.
"China will not listen to Japan about the [Diaoyu] Senkakus; it is only the United States that can deter their actions," said Yukio Okamoto, former special adviser to prime ministers Ryutaro Hashimoto and Junichiro Koizumi, in a September 2013 speech. "The United States has an even bigger role—to not only mediate, but create a new framework of cooperation in the region."
The Okinawa Issue
One of the most contentious issues in the alliance has been the stationing of U.S. Marines on Japan's Okinawa prefecture, which hosts around 65 percent of total U.S. forces in Japan and is also the poorest of Japan's forty-seven prefectures. Locals deeply resent the outsize burden of hosting U.S. troops at the Futenma base and have voiced serious concerns about the accidents and incidents of crime (including recurring cases of sexual assault) that have persisted on the base. The gang rape of a twelve-year-old girl in 1995 by three U.S. servicemen galvanized eighty-five thousand locals to protest. A year after the mass demonstration, then prime minister Ryutaro Hashimoto directly asked then U.S. president Bill Clinton to return Futenma to Japanese control. Other allegations of sexual violence by U.S. military personnel in Okinawa surfaced in 2008 and 2012, and various plans for relocating Futenma were put forward, but they were met with local opposition.
In a more recent bid to reconcile tensions, the United States and Japan agreed in May 2006 to a U.S.-Japan Roadmap for Realignment Implementation that would relocate the Futenma Air Station out of the crowded city of Ginowan, build a new runway in the waters off of Camp Schwab, and transfer eight thousand Marines to Guam. But this proposal devolved into a political maelstrom when the Democratic Party of Japan's Yukio Hatoyama, who opposed the relocation during his campaign, became prime minister in 2009.
Since then, Washington and Tokyo have made other overtures to resolve the long-standing issue. The two parties altered the pact in April 2012, disconnecting the transfer of Marines from the construction of the new base, and in April 2013 they reached a deal to return Futenma—and five other U.S. bases—by the late 2020s.
"It's been very corrosive for the alliance," Smith says of the Okinawa issue. "It has focused our attention on this one particular base, when the real challenge for the alliance has been to come up with a broader framework for the sustainability of U.S. forces in Japan."
The Future of the Alliance
The coordination between U.S. and Japanese military forces after the devastating March 2011 earthquake and consequent tsunami that struck Tohoku demonstrated the resilience of the alliance. The SDF conducted rescue operations in tandem with thousands of U.S. forces under Operation Tomodachi, the largest bilateral mission in the history of the alliance. U.S. forces aided the SDF in clearing Sendai's airport, assisted in search-and-rescue teams, and prepared Japan's defense readiness.
This high level of support echoed Japan's own cooperation during the Gulf and Iraq wars. In November 2001, the government of Junichiro Koizumi dispatched the Maritime Self-Defense Force to the Indian Ocean to support U.S. military operations in Afghanistan, marking Japan's first overseas military action during a combat operation. A year later, Japan drafted a bill that would allow the SDF to be dispatched to postwar Iraq, and in 2003 it sent forces to aid in postwar reconstruction efforts.
At a 2 + 2 meeting in early October 2013, the United States agreed to deploy reconnaissance drones to Japan, which also pledged up to $3.1 billion to relocate five thousand U.S. Marines from Okinawa to Guam. Ministers also agreed to rewrite the guidelines for U.S.-Japanese Defense Cooperation for the first time since 1997 in revisions that would expand cooperation on counterterrorism and bolster the allies' ability to respond to an attack on Japan.
"The United States has an even bigger role—to not only mediate, but create a new framework of cooperation in the region." —Yukio Okamoto, former special adviser to prime ministers Ryutaro Hashimoto and Junichiro Koizumi
In July 2014, Japan took a step toward a more active role in regional security when Abe announced that his cabinet had approved a reinterpretation of the antiwar Constitution that would allow Japanese forces to aid friendly nations under attack. The decision marks a significant shift from a position that had strictly limited Japan to act solely in its own defense. "Japan, for half a century, has expanded its military capability in ways that raise questions about the interpretation of Article Nine in its constitution," says Smith. "And the question has become, 'How much can Japan do in the alliance?'"
Some experts have defined the modern-day alliance to be more inclusive, advocating initiatives such as trade and energy cooperation as the road to a future framework. "This is bigger than just the military. These are instruments we use to improve our own national prosperity and security, and that's fundamentally what this alliance should be about," Smith says.
The multilateral Trans-Pacific Partnership has been a highly promising economic development that observers hope will tighten the alliance. After the Fukushima nuclear disaster forced Japan to reconsider its energy policies, Washington agreed to a long-term liquefied natural gas export deal with Japan that could see the United States become a supplier for the island country.
"This is the most relevant the alliance has been in a long time," says Lind. "With the ebb and flow of what's going on in the region, these are two countries that are highly incentivized to make this work."
CFR's Sheila Smith delves into how the U.S.-Japan alliance fits into Asia's shifting geopolitics in this World Politics Review article and outlines a strategy for the alliance in this CFR Policy Innovation Memorandum.
George Packard reflects on the alliance on its fiftieth anniversary and debates its efficacy in this 2010 Foreign Affairs article.
Richard Armitage and Joseph Nye recommend steps forward for the U.S.-Japan Alliance in this 2012 Center for Strategic and International Studies report [PDF].
Yasuhiro Izumikawa explains Japanese antimilitarism and explores theories of Japan's postwar security policy in this 2010 International Security article [PDF].