A Vital Next Step for the U.S.-Japan Alliance: Command and Control Modernization

One year after the release of historic national security and defense strategies, Japan is moving with striking speed to build a more credible Self-Defense Force (SDF), capable of responding rapidly to threats in a challenging security environment. As Japan enters the second year of its buildup, defense spending is already up 50 percent over 2022 levels. In addition to significant investments in counterstrike capabilities, munitions stockpiles, and SDF readiness, it has announced major structural reforms to the SDF as well—in particular, plans to establish a Japan Joint Operations Command (J-JOC) by 2025 to direct all SDF joint operations. This is a significant reform, one that was long debated and long delayed, and it represents a victory for advocates of increased jointness as key to the deterrence and response capabilities of the SDF.

The speed with which Japan is moving to strengthen defense capabilities increases the importance of the next step in U.S.-Japan alliance transformation: modernizing its command-and-control architecture. As Japan becomes a more capable military partner, Washington and Tokyo need to build new structures to support a more operational alliance. A transformed command and control architecture would significantly enhance the credibility of the alliance and help to reinforce deterrence in East Asia. Japan’s planned acquisition of counterstrike capability lends particular urgency to this effort; for the first time, the United States and Japan will need to be able to coordinate the use of force, both tactically (identifying and prosecuting targets) and strategically (managing escalation in a conflict). 

Reimagining U.S. Forces Japan

The current structure of alliance command and control is not sufficient for the task. U.S. Forces Japan (USFJ) has changed little since the 1960s, when Japan was viewed as little more than a platform for U.S. military operations across the region. USFJ’s authorities and staffing are limited primarily to administering alliance agreements related to the 50,000-plus U.S. personnel stationed in Japan with the U.S. Navy, Marine Corps, Air Force, and Army. U.S. forces in Japan represent some of the most important U.S. military capabilities in the Indo-Pacific, but the three-star USFJ commander has limited joint operational authorities, and the separate U.S. service elements in Japan report back to their component headquarters in Hawaii.

The inadequacy of existing alliance command and control is increasingly recognized in both Washington and Tokyo. The U.S. Congress in the 2024 National Defense Authorization Act required a Defense Department feasibility study (due in June) on modifying U.S. command structures in Japan to complement Japan’s establishment of the J-JOC.

But if the need for modernization seems obvious, the specific solution to improve alliance command and control is complex and involves myriad stakeholders. To foster bilateral dialogue on the topic, the authors have been collaborating for over a year with a wide range of experts, retired military and government officials, and currently serving officials from both countries—all with long alliance experience—to consider and debate options for modernizing the architecture of the alliance. The initiative produced a mid-term report last May, and a final report is forthcoming. The views here represent the personal views of the authors, based on this work.

A U.S. Joint Force Headquarters in Japan

A central conclusion of these deliberations is the need for a forward U.S. joint operational command element in Japan to serve as the standing, day-to-day counterpart for Japan’s new J-JOC. It is up to the two governments to determine how to accomplish this vision in detail, but with the benefit of several bilateral workshops and input from many experts, the authors can offer some general recommendations.

First, to provide for the focused planning and execution of U.S.-Japan bilateral missions, the United States should transform USFJ into a fully capable three-star Joint Force Headquarters, subordinate to INDOPACOM, who can work with the J-JOC deputy commander, also a three-star, on a daily basis. Japan’s new J-JOC will be led by a 4-star officer of equivalent rank to Japan’s service chiefs, supported by a staff of about 240 personnel and located within the Defense Ministry in Tokyo. Although the J-JOC Commander’s U.S. leadership counterpart will be the commander of U.S. Indo-Pacific Command (INDOPACOM), the command in Hawaii has vast regional responsibilities that limit its ability to focus on the day-to-day relationship with Japan. The J-JOC warrants, and the alliance would benefit from, a true U.S. joint operational counterpart located in close proximity.

The “new” USFJ should have enhanced authorities and the necessary staff to support this role, with the capacity to expand in size and responsibilities when needed to support operations in a major contingency. USFJ today is relatively small, with about 150 assigned personnel, so transforming it will require perhaps 100 additional personnel and the authorities to plan and execute bilateral exercises, training, and missions approved by U.S. Indo-Pacific Command (INDOPACOM). The ultimate size of the new USFJ will depend on the scope of these missions. Congress will need to appropriate funds for this effort, although the amount would not be large, in the context of an $800 billion defense budget and a defense strategy focused on the “pacing threat” of China. One possible vehicle for these additional funds could be the Pacific Deterrence Initiative, a subset of the Defense Department’s budget that is focused on efforts to strengthen deterrence against China, including by strengthening the capabilities of allies and partners.

The commander of this “new” USFJ could still retain existing responsibilities as the senior U.S. military representative to the Japanese government, but would accrue additional authorities as the day-to-day operational counterpart to the J-JOC. The revamped USFJ should have a defined Area of Responsibility—such as missions in the defense of Japan and supporting regional contingency operations—that could be modified with direction from INDOPACOM.

The new USFJ Joint Force Headquarters need not have permanently assigned forces. For the most part, U.S. forces stationed in Japan would operate on a routine basis as they do today, under the authorities of component commands in Hawaii reporting to INDOPACOM. However, with a joint operational command structure in place, the United States and Japan would be better postured to expand bilateral military operations when needed, from peacetime to major contingencies. In any major regional contingency—on the Korean Peninsula, in the Taiwan Strait, or beyond—Japan will play an increasingly important role as its capabilities expand. A U.S. joint operational command in Japan will help ensure close alliance coordination in a crisis.

Integrating U.S.-Japan Command and Control

As it transforms USFJ, the United States should simultaneously work with Japan to establish a standing bilateral joint planning and coordination office that can support planning, exercising, and execution of specific bilateral missions. With the J-JOC up and running, and a counterpart U.S. joint headquarters in place, the next step should be a colocated, standing bilateral planning and coordination office that can plan and support alliance operations in real time. No such structure exists today.

This is a politically sensitive topic, especially in Japan, where constitutional restraints on the military remain strong and concerns about entrapment in a U.S. military conflict endure. But the logic of greater integration of alliance command and control is incontrovertible.

To build public support, Washington and Tokyo should begin with an articulation of principles to guide the development of a bilateral C2 architecture, to help engage the public and build support in both countries. These principles could include the following:

  • Parallel but Separate Chains of Command: This is to preserve accountability to national political leadership. For legal and political reasons, a truly combined command, like that between the United States and South Korea, is neither feasible nor necessary. The goal should be closer integration, to support bilateral missions that serve alliance objectives—while preserving separability.
  • Respect for National Legal Authorities: This is with regard to planning and executing bilateral missions. Building on the first principle, bilateral missions would not extend beyond the constitutional and legal limits of either country—for example, Japan’s limits on collective self-defense.
  • Colocation of Personnel in a Joint, Bilateral Planning and Coordination Office: This office would be staffed with personnel from uniformed services of both countries. This staff would serve as an alliance unit that supports each nation’s command authorities in Japan.
  • Civilian Control of Bilateral Operations: This includes close connectivity to the alliance’s civilian-led decisionmaking. The new bilateral joint coordination office should coordinate with the civilian-led dialogue channels that Washington and Tokyo utilize to help direct the alliance.
  • Connectivity with Other Bilateral Alliances: This includes Combined Forces Command in South Korea and Australia’s Joint Operations Command, to expand information sharing and enhance coordination.

A more integrated U.S.-Japan alliance, through a strengthened USFJ and a standing bilateral planning and coordination office, will reinforce deterrence and regional stability by enabling a more seamless alliance response to crises and strengthening cooperation in peacetime. Bilateral missions the task force could oversee include air and missile defense; intelligence, surveillance, and reconnaissance collection and analysis; logistics and “lift” of personnel and supplies; cyber defense; asset protection; maritime security; search and rescue; and operationalizing Japan’s new counterstrike capability with some U.S. support.

It's Time to Think Big

These are not small steps: they will take time and resources to execute with support from the Congress, but high-level alliance meetings this year can provide direction and a framework for implementation. Prime Minister Kishida is scheduled to visit the White House April 10, and a “2+2” meeting of the allies’ defense and foreign policy leaders will likely follow soon thereafter. The heads of state should put alliance command and control modernization on the bilateral agenda, and the 2+2 can set its future course and begin to identify principles that guide detailed planning.

The time to modernize the U.S.-Japan alliance’s 60-year legacy arrangement is now, not only because of changing threats and technology, but also because of the opportunity that is presented by Japan’s development of the J-JOC and dramatically improved defense capabilities. There are a host of political, cultural, legal, and institutional complications to navigate, but these should not be a barrier to action. It is time to move on from this legacy architecture and embrace the promising future that awaits.

Christopher Johnstone is senior adviser and Japan Chair at the Center for Strategic and International Studies in Washington, D.C. Jim Schoff is senior director at Sasakawa Peace Foundation USA.

Jim Schoff

Senior Director, Sasakawa Peace Foundation USA