Ishiba Shigeru, who assumed office as Japan's new Prime Minister in October 2024, attracted considerable attention during the Liberal Democratic Party (LDP) leadership election by presenting proposals in the area of foreign and security policy that differentiated him from the prevailing approach, including the establishment of an Asian version of NATO, the revision of the Japan-U.S. Status of Forces Agreement (SOFA), and the creation of a Japan-North Korea liaison office. In his first address to the Diet following his inauguration, he emphasized the strengthening of the deterrence and response capabilities of the Japan-U.S. alliance, the deepening of Japan-South Korea cooperation, and the building of a constructive relationship with China, while avoiding specific reference to the contentious security agenda items he had advanced during the election campaign. Against this background, assessments have been raised that Ishiba's foreign and security policy has yet to secure broad public support, amid ongoing debate over its feasibility.

Ishiba's security vision faces considerable obstacles to near term realization when considered in light of Japan's constitutional and institutional constraints, the deepening of U.S.-China strategic competition, the cautious posture of Asian nations, and United States foreign strategy. Nevertheless, careful deliberation is underway within the LDP on proposals such as an Asian NATO framework and discussions on nuclear sharing. In particular, the inauguration of the Trump administration in the United States in 2025 is likely to serve as an important variable in determining the direction in which the Ishiba government's foreign and security policy will be sustained or transformed.

The foreign and security policy of the Ishiba government largely carries forward the existing policy trajectory established through the Abe, Suga, and Kishida administrations. The foreign and security policy orientation that Japan has built through the formulation and revision of its National Security Strategy in 2013 and 2022 has been pursued consistently, centering on increases in defense expenditure to address China's military buildup and North Korea's missile threat, and the preparation of contingency measures related to a Taiwan emergency. The Ishiba government likewise maintains this policy continuity while further strengthening Japan's security posture. At the same time, Ishiba has signaled a differentiation from the existing orientation by emphasizing the equalization of the Japan-U.S. alliance and the enhancement of Japan's autonomy in foreign and security affairs. In particular, the Asian NATO concept and the revision of the Japan-U.S. SOFA are assessed as attempts to pursue the strengthening of Japan's independent security capabilities. However, the prevailing view is that these proposals will be difficult to realize in the near term, given the cautious posture of Southeast Asian nations, the need for consultations with the United States, and the absence of domestic political consensus.

The limitations of the Ishiba government are also becoming apparent in its policy toward North Korea. Following the LDP's defeat in the October 2024 House of Representatives election and the decline in the Ishiba cabinet's approval ratings, the government has found itself with diminished capacity to engage proactively in dialogue with North Korea. On the surface, it maintains the posture of seeking an "unconditional meeting with Kim Jong-un," but in practice it has not pursued informal contacts as actively as the preceding Kishida government. Furthermore, changes in the international environment, including the deepening of North Korea-Russia cooperation and the prolongation of the Russia-Ukraine war, are pushing Japan toward strengthening its military response capabilities and deepening the Japan-U.S. alliance and trilateral Japan-U.S.-South Korea cooperation.

In this process, the Ishiba government perceives China, rather than North Korea, as the primary security threat, and discussions on an Asian NATO framework and nuclear sharing are likewise interpreted as moves undertaken with an eye toward counterbalancing China.

This divergence in perception is likely to serve as a significant variable in the future trajectory of Japan-South Korea relations. Japan is focused on strengthening the defense of its southwestern region, including contingency preparations related to a Taiwan emergency and the defense of the Senkaku Islands, whereas South Korea continues to regard North Korea's nuclear and missile threats as its foremost security concern. Accordingly, differences in the priorities of Japan-South Korea security cooperation may become more pronounced, and South Korea will need to carefully develop a response strategy grounded in trilateral South Korea-U.S.-Japan coordination that takes these circumstances into account. In particular, substantive advances in cooperation are required, including the regularization of joint military exercises grounded in the spirit of the Camp David agreements concluded in 2024 and the establishment of a real time sharing system for North Korean missile information.

The Ishiba government's power base is fragile, and the possibility of a change in leadership following the July 2025 House of Councillors election has been raised. However, even should the Ishiba cabinet be replaced, the broad framework of Japan's foreign and security policy is expected to maintain continuity with Abe era diplomacy, and the security issues raised by Ishiba are likely to remain at the center of debate both within the LDP and between the ruling and opposition parties. Given that Japan is pursuing a dual strategy of simultaneously advancing the strengthening of the Japan-U.S. alliance and expanding security autonomy, South Korea will need to take a proactive role in setting the agenda for Japan-South Korea and trilateral South Korea-U.S.-Japan cooperation within the complex security order of the Indo-Pacific region.​