The US National Security Strategy (NSS) 2025 reflects Donald Trump’s vision of “America First” asserting that the US will relocate its focus on securing dominance in the Americas to enable domestic revival. The strategy resurrects the Monroe Doctrine as a “Trump Corollary” and states that Washington will “deny non-Hemispheric competitors the ability to position forces or other threatening capabilities…in our Hemisphere”. The NSS goes so far as to propose a repositioning of US military forces back to the Western Hemisphere, moving assets “away from theaters whose relative import to American national security has declined”. Focusing on this hemispheric dominance comes at the cost of reduced attention on the Indo-Pacific. As reflected in the NSS, China is not mentioned a primary military threat but rather an economic competitor. Hence, the NSS has downgraded China from a “pacing threat” to merely an economic rival. While the strategy declares Asia as a battlefield of economic and technological competition, it has relegated Syria, Ukraine and Europe to lesser priorities. As the strategy document states that Europe is asked to “stand on its own feet… taking primary responsibility for its own defence”, it seems that unilateralism has replaced alliances. The U.S. may reverse its long-extended security umbrella. Hence, the outsourcing of burdens to allies, rather than confronting threats head on, illustrates that the US is taking up of strategic retrenchment and buck-passing.
The US Buck-Passes: Implications for Japan
For Japan, the 2025 NSS signals a sharp contraction of the U.S. security umbrella. China is now treated chiefly as an economic rival, and the Indo-Pacific is no longer billed as the central arena of U.S. interests. Meanwhile, Washington’s stated policy is to demand Japan do more: not only to spend up to 2% of GDP on defense (a goal Tokyo hastened to meet by 2025), but even to exceed it “beyond the 2% threshold” during U.S. talks. In practice, this means Tokyo can no longer rely on automatic American intervention. As the NSS warns, U.S. forces will defend Taiwan or the First Island Chain only insofar as allies “step up” their own capabilities.
Japanese officials recognize the shift. Tokyo’s response has been to accelerate militarization and strategic autonomy. In late 2025 Prime Minister Sanae Takaichi announced a plan to double Japan’s defense budget to 2% of GDP by FY2025, which is two years earlier than planned and signaled willingness to go higher. At the same time, its rhetoric has grown pointed. Takaichi’s comment in November 2025 that a Chinese occupation of Taiwan would be “a situation threatening Japan’s survival” reverberated through Beijing. Although, the statement was in line with a 2015 security legislation that broadly defined a “survival-threatening situation”, it was an evident departure from years of careful ambiguity. By mentioning that threshold, Takaichi indicated Tokyo’s resolve in directly challenging Chinese aggression.
With America signaling retrenchment, Japan’s moves are rational and it must prepare to defend itself. China is modernizing its military and now openly contests Japan’s proximity. In 2025 alone China scrambled jets near the Senkaku Islands and threatened retaliation over Tokyo’s Taiwan comments. Under these conditions, expanding the Self-Defense Forces is a logical adaptation. Indeed, Japanese analysts note that Tokyo’s latest plans to acquire offensive missiles, reinforce bases, and even consider nuclear cooperation amount to a “new dawn” in Japan’s security policy. Hence, Japan is not blindly arming; it is responding rationally to an eroding U.S. guarantee.
Japan’s Militarization: A Necessary and Historic Shift
As the region is already experiencing China’s intrusions around Taiwan and Japan’s air defense zone, the long-resisted remilitarization of Japan, therefore, is necessary as well as timely. Japan cannot remain defenseless. Hence, it is raising defense spending high above the historical norm of 1% of GDP to hitting 2%. Moreover, it is boosting its defense capabilities directed right at deterring China.
Crucially, Japanese leaders cast this shift as breaking free from the pacifist mold. Although Japan must still depend for its security on U.S support, Japan’s Chief Cabinet Secretary Minoru Kihara described the Japan’s position that it will move toward a more robust defense posture “for our own reasons”. In this purview, the long-standing debate over “postwar pacifism” should be put to rest. The 2015 laws ended Japan’s strict self-defense-only posture, and the Takaichi policies has made it clear that the era of willful weakness is over. In assuming the responsibilities of a major power, Japan is availing a historical opportunity.
With a rising China, Japan has very little wiggle room. Now, Japan has to stand as regional hegemon on its own, without a support from the U.S. In material terms, Japan’s military build-up will turn it into a pivot of the security architecture of the Indo-Pacific that will add to the its deterrence and help maintain to regional balance.
Japan in a New Regional Order
Hence, the NSS does signal that the U.S. is deliberately reducing its global role and passing costs on to allies. Washington’s approach is buck-passing, communicating Japan, South Korea, Australia and Europe to defend themselves. This forces a fundamental shift. In response, Japan, in particular, has truly stepped up. It is rationally modernizing its military and rethinking its strategy, casting off relics of postwar pacifism. In the coming years Japan will wield for greater security capabilities. With China’s aggressiveness, a stronger Japan for itself is not provocatory, but a pragmatic necessity. Therefore, in the new Indo-Pacific balance, Japan’s militarization is a prudent bid for stability.
