【Cooperation between European and Indo-Pacific Powers in the US alliance system project：Policy Paper Vol. 8】
Cooperation by Design: The Implication of Maritime Connectivity for NATO and the Indo-Pacific Partnership

Publication of Policy Papers for the SPF Project “Cooperation Between European and Indo-Pacific Powers in the U.S. Alliance System”

　IINA (International Information Network Analysis) hosts a series of policy papers featuring analyses and insights from U.S., Japanese, South Korean, Australian and European experts, which discuss constructive cooperation among U.S. allies in Europe and the Indo-Pacific. The series aims to provide readers with valuable perspectives on the future of NATO-IP4 (Indo-Pacific 4) cooperation for regional and global security.

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This paper argues that the partnership between NATO and Japan shifted from cooperation by chance to cooperation by design after 2001, when Japan suddenly expanded its cooperation with NATO due to common challenges in Afghanistan. The September 11 terrorist attacks dramatically changed the strategic landscape and transformed Japan’s position as the lead country of a pacifist foreign policy of demobilization, demilitarization, reintegration, and post-conflict reconstruction. One way to describe this partnership between NATO and Japan is cooperation by chance.

The present partnership between Brussels and Tokyo has become much more structured and truly global. For example, NATO and Japan signed an individually tailored partnership program at the 2023 NATO summit.[1] Both acknowledge the interconnectivity between the Euro-Atlantic and Indo-Pacific theaters, as their common efforts to support Ukraine since Russia’s 2022 invasion symbolize. NATO-Japan interconnectivity is enhanced by their maritime connectivity, which Tokyo’s concept of a Free and Open Indo-Pacific enshrines. NATO and Japan both support this concept and have enabled this shared understanding not by chance but by design.

The change in the NATO-Japan partnership has not only occurred at the strategic level but has also been brought about by changes at the theater and tactical levels.

Challenges in Connectivity: The Strategic Level

In recent years, NATO member states and Japan have been upgrading their defense force postures that provide extended deterrence to remain credible in the face of new threats. The 2022 Russian invasion of Ukraine resulted from a deterrence failure in Europe. Yet there has been no armed attack on NATO member states bordering Ukraine. In this context, NATO can claim that allied extended deterrence is “ironclad.” Article 5 obligations of collective defense in the event of a violent attack on a NATO member state have historically been at the core of Euro-Atlantic ties. The revised 1960 US-Japan alliance treaty also contains an Article 5 obligation, and that allows NATO and Japanese defense officials to have a similar operational picture.

This strategic level of connectivity received unprecedented attention in 2024, highlighting some advantages and drawbacks of the NATO-Japan relationship. One advantage is that both sides agreed that Russia’s invasion of Ukraine posed a security challenge to US allies in both Europe and the Indo-Pacific. Consequently, at NATO’s seventy-fifth summit in Washington, DC, in July 2024, Japan participated as an IP4 partner alongside South Korea, Australia, and New Zealand. Ukraine and the EU also participated, which implied that NATO’s primary focus at the summit was support allowing Ukraine to maintain a resilient force posture. Specifically, there was a huge demand for supporting security sector reform in Ukraine, and IP4 supported this prioritization.

Resilience support for Kyiv constitutes a common NATO-IP4 approach to the necessity of supporting Ukraine’s war effort. Such support maintains credible deterrence of Russia while avoiding active engagement in a war outside NATO’s area of responsibility: Ukraine is not an official NATO member under the protection of its collective security guarantees. On the other hand, Kyiv is an important partner that shares national borders with many NATO member states. In this complex situation, NATO has agreed that resilience support for Kyiv is the best way to uphold credible deterrence. Japan has embraced this concept by forming a security accord with Kyiv,[2] which one could label extended deterrence plus. Washington and Tokyo could develop a similar format to prevent a contingency in the Taiwan Strait.

A second advantage of strategic connectivity between NATO and Japan is the incentives that European countries have offered for contributing to deterrence in the Indo-Pacific. In 2024, vessels from European NATO members including France, Germany, Italy, and the Netherlands joined the RIMPAC exercise as a joint Indo-Pacific deployment. Implementing maritime connectivity across the Euro-Atlantic and Indo-Pacific theaters and aligning it with mutual expectations of the limits of out-of-area engagements are important steps for strengthening deterrence across the Euro-Atlantic and Indo-Pacific theaters. NATO’s primary obligation is the Euro-Atlantic theater, and IP4’s is the Indo-Pacific theater. Successful conflict management requires expectation management on both sides.

The drawback of strategic connectivity between NATO and Japan is that strategic competitors are strengthening their cooperation across the Euro-Atlantic and Indo-Pacific theatres, thereby challenging the strength of US allies’ commitment across the two theaters. For example, in June 2024, North Korea and Russia signed the Treaty on Comprehensive Strategic Partnership allowing for mutual military support. The treaty underpinned North Korea’s commitment to support Russia’s war in Ukraine with troops and ammunition. Russia–North Korea military cooperation in the European theater of war demonstrates the threats emanating from the interconnectedness of the Euro-Atlantic and Indo-Pacific theaters.

Challenges in Connectivity: The Theater Level

Japan’s Free and Open Indo-Pacific concept highlights the economic and political interdependence between the Euro-Atlantic and Indo-Pacific regions. This interdependence influences the management of maritime connectivity. Russia and China pose a rising two-front threat to America’s allies. Japan’s response to strategic competitors’ cooperation across the Euro-Atlantic and Indo-Pacific theaters has been to review the posture of Japan Self-Defense Forces (JSDF). This includes a comprehensive review of the command and control structure of the Japan Maritime SDF (JMSDF).

In September 2024, the Japanese Ministry of Defense announced that the JMSDF will abolish the Fleet Escort Force (FEF) and the Mine Warfare Force (MWF) and instead build up a Fleet Surface Force.[3] Japan established the FEF in 1961 with four escort flotillas in Yokosuka, Kure, Sasebo, and Maizuru. Its primary mission was to defend Japan’s territorial waters and surrounding seas, in line with the country’s post–World War II concept of exclusively defense-oriented military forces. However, new concepts need to include tailored amphibious warfare and mine warfare operations.

The JMSDF review reflects the strategic competition between the US, Russia, and China. Japan’s 2023 National Security Strategy already articulated this premise, requiring the SDF to engage in multidomain operations across the Indo-Pacific. JMSDF’s new mission will be to ensure stability in the East and South China Seas, including the Taiwan Strait. Tasking the JMSDF with operational responsibilities in these areas is not new. What has changed is JMSDF’s command structures.

Challenges in Connectivity: The Tactical Level

Japan has designed the reorganization of its JMSDF to deal with multiple theaters of war. It views this as necessary due to strengthened military and dual-use cooperation between China, Russia, and North Korea. JMSDF is similar to the US Navy’s Distributed Maritime Operation (DMO) approach, which the United States adopted in response to the strengthened anti-access / area denial (A2/AD) posture of China and its strategic partners.[4] The JMSDF’s introduction of 400 Tomahawk cruise missiles and its redesign of the helicopter carriers Hyuga and Ise to accommodate F-35B fighter aircraft are examples of the DMO approach.

The reorganization of JMSDF is also in line with the objectives of NATO’s 2023 ITPP with Japan. As “reliable and natural partners,”[5] Brussels and Tokyo will respond to common challenges, such as maritime connectivity and EDTs.

NATO and the Indo-Pacific Partnership: Cooperation by Design

A look back at the history of NATO-Japan cooperation shows 9/11 was a turning point. The terrorist attacks led NATO and its partner states in the Indo-Pacific and elsewhere to contribute to the Global War on Terror. These states engaged in peacekeeping and peacebuilding missions and activities in Afghanistan and Iraq, but their efforts did not result in lasting peace.

Stabilization and reconstruction in Afghanistan and Iraq required the establishment of long-term, high-level maritime connectivity, mainly for logistical support and reconstruction. Provincial reconstruction teams, the International Security Assistance Force, and many other interlocutors coordinated these efforts. Meanwhile, JMSDF supported Operation Enduring Freedom with refueling missions. First, Japan deployed forces in the Indian Ocean to support US Navy vessels. Gradually, JMSDF expanded its cooperation, supporting partner countries other than the US. These operations were a learning process for the JMSDF that taught them to operate according to NATO standards.

NATO-Japan relations started as cooperation by chance. However, with the emergence of strategic competition with states such as Russia, China, and North Korea, the partnership has evolved into cooperation by design, connecting the Euro-Atlantic and Indo-Pacific maritime theaters.

(2025/03/28)