Japan's government has compressed years of incremental defense reform into a matter of weeks, driven by two parallel pressures: U.S. munitions stockpiles depleted by combat operations against Iran, and deepening uncertainty about the reliability of American security guarantees under President Donald Trump's America First doctrine. The convergence has produced concrete policy action across three distinct lines of effort in rapid succession.
On April 21, Prime Minister Sanae Takaichi's Cabinet formally approved revised guidelines under Japan's "Three Principles on Transfer of Defense Equipment and Technology," eliminating a longstanding restriction that had confined weapons exports to five non-lethal categories, including rescue, transport, and minesweeping equipment. The Cabinet's approval of the new guidelines clears a final set of hurdles for many arms sales, including Japanese-developed warships, combat drones, and other weapons. The Cabinet classified defense equipment into two categories, "weapons" and "nonweapons," with decisions on lethal exports to be examined by the National Security Council and limited to countries that have signed defense equipment and technology transfer agreements with Japan. Japanese companies may now sell arms to 17 countries with which Tokyo holds such agreements, including the United States, the United Kingdom, Australia, and multiple Southeast Asian nations. The constitutional basis for the prior restrictions traces to Article 9 of Japan's 1947 constitution, which renounces "the threat or use of force as a means of settling international disputes." The Takaichi government, like its predecessors, is proceeding by executive reinterpretation rather than formal constitutional amendment. Domestic opposition parties and civil society groups warn that these incremental changes risk eroding the substantive meaning of Article 9.
The arms export liberalization coincided with separate moves on naval doctrine and alliance architecture. A group of 30 NATO representatives visited Japan to discuss deepening ties as U.S. commitment to the alliance has been shaken by President Trump. Japan's government has also been pressing revisions to its 2022 National Security Strategy to extend naval operations to regional sea lane defense, building on the strategy's existing mandate for "significant reinforcement of maritime security capabilities." Since her election as prime minister, Takaichi has pledged a "new golden age of the Japan-U.S. alliance" while committing to raise defense spending to 2% of GDP ahead of schedule and expedite revision of three major national security documents. Japan's Cabinet approved a supplementary budget poised to exceed 2% of GDP in defense spending for the current fiscal year, adding approximately $7 billion in additional defense funds, bringing total spending to roughly $70 billion.
The Iran conflict has created a direct material constraint on Japan's rearmament timeline. Japan's order for hundreds of Tomahawk cruise missiles, a centerpiece of its long-range strike capability strategy, is under threat as U.S.-Israeli combat operations against Iran deplete inventories, with Washington informing Tokyo that deliveries for its order of approximately 400 missiles by March 2028 would be disrupted. Japan signed a foreign military sales agreement for those missiles in January 2024, acquiring 200 Block IV and 200 Block V Tomahawks and associated weapons control systems at an estimated cost of $2.35 billion. The supply gap is significant: RTX produced roughly 100 new missiles in 2025, while about 240 older models were upgraded to the Block V standard, and more than two years' worth of combined production has been consumed so far in the conflict. The United Kingdom, Australia, and the Netherlands also purchase Tomahawk missiles, and efforts to ramp up production to 1,000 units per year, a new Pentagon goal outlined in a February framework agreement with RTX, could take years to materialize. Japan has responded in part by accelerating indigenous missile deployment: its extended-range Type-12 missile, produced by Mitsubishi Heavy Industries with a range of roughly 620 miles, has been deployed to a base in Kumamoto, southern Japan.
The Tomahawk delay and the constitutional refusal to deploy forces to the Strait of Hormuz when requested by the Trump administration have together crystallized for Tokyo the limits of dependence on a single security partner. For Japan, the Trump administration's 2025 National Security Strategy signals a contraction of the U.S. security umbrella, with China treated chiefly as an economic rival and the Indo-Pacific no longer designated the central arena of U.S. strategic interest. China has rapidly enhanced its military capabilities in a qualitative and quantitative manner and intensified activities in the East China Sea, including around the disputed Senkaku Islands. Former U.S. Ambassador-designate to Japan Ken Weinstein, citing conversations with senior Japanese officials, told POLITICO that "Japan has gotten the memo that the United States wants it to step up as a defense-oriented peer and not as a protectorate," adding that there is "a definite fear of U.S. isolationism." [POLITICO] The White House has signaled acceptance of that trajectory. White House spokesperson Anna Kelly told POLITICO that "President Trump has encouraged all of our allies to take greater responsibility for their own defense." [POLITICO] Japan's current moves, taken together, constitute not a discrete policy decision but a structural reorientation: diversifying its defense partnerships, building indigenous strike capacity, and recalibrating a constitutional framework that has defined its security posture for eight decades.
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[1] PBS NewsHour. (2026, April 22). Japan lifts ban on lethal weapons exports in major change of its postwar pacifist policy. https://www.pbs.org/newshour/world/japan-lifts-ban-on-lethal-weapons-exports-in-major-change-of-its-postwar-pacifist-policy
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