The Biden-Kishida summit should set the stage for a unified U.S.-Japanese military command

President Biden will host Japanese Prime Minister Fumio Kishida and Philippines President Bongbong Marcos next week in a trilateral summit intended to further strengthen ties among the three allies. Biden will also meet separately with both leaders, with Kishida on April 10 and with Marcos the following day.

Both Asian countries have committed to increasing their defense spending. Manila plans to spend an addition $35 million over the next decade, while Japan has committed to expending nearly ten times as much — $300 billion — by 2027. Tokyo’s defense program will nearly double the 1 percent of GDP that it currently allocates to defense.

Few doubt that Japan will realize its ambitious defense buildup by 2027. On the other hand, it is not at all clear that the country can sustain its planned level of defense expenditure well beyond the end of this decade, due to a reduced tax base resulting from Japan’s population decline.

The drop in the country’s population is a product of both low birth rates and an aging cohort. Japan’s population, which stood at 123 million in 2022, shrank by nearly 1.3 million over the past two years. The number of babies born in the country fell for the eighth consecutive year in 2023, with no immediate prospect of an upturn. By 2030, Japan’s population is estimated to stand at around 117.5 million, with an increased proportion of the elderly; the number of citizens over 65 will rise from 28.5 million to 29.6 million. As Japan’s tax base declines, demands for greater social welfare spending on its aging population will increase.

Moreover, Japan’s debt-to-GDP ratio currently stands at about 260 percent, second highest in the world after Venezuela. Although it is projected to drop somewhat in the next few years, that ratio will remain exceedingly high. All these developments will likely result in tremendous pressure on future governments to constrain the levels of defense spending to which the country is now committed.

Given likely future pressures on Japan’s defense budget, there is much to be said for increasing the synergies that could be realized from ever-closer cooperation with the United States, which faces its own long-term pressures on defense spending. Next week’s Biden-Kishida summit likely will outline a number of steps in that direction.

The Biden administration is expected to announce that it will upgrade from three-stars to four-stars the command of U.S. forces in Japan. For his part, Kishida is planning to establish by 2025 a new Self-Defense Forces headquarters that would oversee all Japanese military operations. It too would be commanded by a four-star officer.

At a minimum, the American commander would be responsible only for joint exercises, training and information sharing with the new SDF headquarters. But there is a strong case for going further and creating a unified command that would incorporate both American and Japanese forces.

There is precedent for such a command. American and South Korean forces have been joined under the Combined Forces Command since 1978. The CFC has operational control over some 600,000 active-duty personnel from both countries, and currently would have wartime control over all South Korean forces and American units deployed to the country. The CFC, which is led by an American four-star general with a Korean four-star as deputy commander and has binational manning throughout the ranks, could serve as a model for a future U.S.-Japanese unified force.

The joint American-Canadian North American Aerospace Command (NORAD) offers another (though somewhat different) model of joint operations between America and one of its leading allies. NORAD focuses on operations related to but a single mission, the defense of American and Canadian air space. Moreover, unlike CFC, the NORAD top command consists of an American four-star general but a Canadian three-star.

What both CFC and NORAD demonstrate in their different ways is that integrated operations between America and Japan are feasible and workable. Given their common perception of the growing Chinese threat and the budget pressures that both countries will face in coming years, Washington and Tokyo should not limit themselves to next week’s expected and welcome announcement of a new stage in their joint military efforts. Instead, they should begin to plan for the establishment of a unified command that would both strengthen their common defense and enhance the credibility of their joint deterrent against an increasingly hostile Beijing, which both countries view as a long-term threat to their national security.

Dov S. Zakheim is a senior adviser at the Center for Strategic and International Studies and vice chairman of the board for the Foreign Policy Research Institute. He was undersecretary of Defense (comptroller) and chief financial officer for the Department of Defense from 2001 to 2004 and a deputy undersecretary of Defense from 1985 to 1987.