A New Phase in the Japan-U.S. Alliance: Strengthening Defense Strategy Under the Takai Administration and Changes in the Northeast Asian Security Environment

In mid-February 2026, the security environment in Northeast Asia is showing several significant developments. In particular, Japan's Prime Minister Sanae Takaichi's proactive defense policy, the strengthening of Russian support for North Korea, and the United States' shipbuilding cooperation plans with its allies indicate a major turning point in the strategic balance in the region.

Since taking office in October last year, Prime Minister Takaichi has promised a "new golden age of the Japan-U.S. alliance" and has stated her intention to raise defense-related spending to 2% of GDP by the end of the fiscal year 2027, two years earlier than planned. This ambitious plan signifies a substantial acceleration of the defense strategy and five-year maintenance plan announced just three years ago in 2022. According to analysis by the Center for Strategic and International Studies (CSIS), Japan is making significant investments in long-range strike capabilities and is set to begin deploying Tomahawk cruise missiles on destroyers starting next year.

However, this enhancement of defense capabilities comes with significant financial challenges. Japan's government debt-to-GDP ratio is about 240%, the highest among advanced countries, and there are substantial constraints on sustained increases in defense spending. Takaichi's two predecessors failed to present clear funding measures, and tax increase plans have not been fully realized. Furthermore, with NATO allies and South Korea and Taiwan announcing plans to raise defense spending to 3.5% of GDP, expectations for Japan have also risen. The next defense maintenance plan, scheduled to be announced by the end of 2026, is likely to call for further increases.

On the domestic political front, the Liberal Democratic Party (LDP) lost its single majority in the lower house last year, and the coalition with the Komeito party, which had lasted for 26 years, has collapsed, bringing unexpected impacts on defense policy. Komeito has played a role in putting brakes on the conservative LDP's defense policies, backed by its pacifist support base. However, the new coalition partner, the Japan Innovation Party, shares many commonalities with the LDP on defense policy and may function more as an accelerator. Nevertheless, this new coalition holds only a narrow majority of 233 seats in the lower house (out of 465) and does not reach a majority in the upper house, raising questions about the sustainability of the administration.

On the other hand, Russia's support for North Korea is significantly deteriorating the regional security environment. Russian Foreign Minister Sergey Lavrov stated on February 11 that he would use the veto to block any new sanctions resolution against North Korea at the United Nations Security Council. He also remarked that discussing North Korea's denuclearization while South Korea, the U.S., and Japan are strengthening "nuclear-inclusive" military cooperation is "unrealistic" and "rude." This marks a complete turnaround from Russia's position prior to 2022. Russia participated in the Six-Party Talks from 2003 to 2007 and voted in favor of ten UN sanctions packages against North Korea from 2006 to 2017.

According to Ukrainian military intelligence, about 8,000 North Korean military troops are deployed around Russia's Kursk region, carrying out fire support missions under the command of the Russian military. North Korea is reported to have initially sent 11,000 to 12,000 troops to the Kursk region in October 2024, resulting in approximately 2,000 combat deaths and 4,000 to 5,000 injuries in frontline combat. Currently, these troops are transitioning to roles in fire support, including artillery operations, multiple launch rocket systems (MLRS) operations, and artillery coordination through aerial reconnaissance. This combat experience is being integrated into North Korea's military training, posing a long-term threat.

Moreover, there are concerns that while Russia opposes South Korea's development of nuclear submarines, it is suspected of supporting similar capability development in North Korea. Russian Ambassador to South Korea, Andrei Kulik, warned on February 9 that South Korea's plan to acquire enriched uranium from the U.S. to build nuclear submarines could violate the Treaty on the Non-Proliferation of Nuclear Weapons (NPT). However, South Korean intelligence reported that in September 2025, Russia provided North Korea with two to three submarine propulsion systems (potentially including operational reactors, steam turbines, and cooling systems). Spanish media reported that the Russian Ministry of Defense's dedicated transport ship "Ursus Major," which sank off the southeast coast of Spain in December 2024, was transporting cooling materials and steam piping components for two Russian-made VM-4SG reactors destined for North Korea's Rajin port.

In this context, the Maritime Action Plan announced by the U.S. on February 19 is noteworthy as a strategic initiative to rebuild U.S. shipbuilding capabilities through cooperation with allies. This plan includes utilizing shipyards in South Korea and Japan, aiming to complement the U.S.'s serious shipbuilding capability shortfall while deepening industrial cooperation with allies. For Japan, this could represent an opportunity for the internationalization of its defense industrial base and the promotion of exports.

Prime Minister Takaichi is focusing on strengthening the domestic defense industry and plans to formulate Japan's first defense industrial strategy by the end of 2026. Earlier this year, Australia's selection of Mitsubishi Heavy Industries for the construction of next-generation frigates indicates that Japan's defense industry is finally emerging as an international player. The LDP and the Japan Innovation Party are also considering plans to relax export regulations on lethal weapons by 2026, which, if realized, would further enhance the prospects for Japan's defense industry.

However, excessive reliance on domestic production carries risks. Japan's defense industry is already under pressure from the demand for defense spending, which has increased by 60% compared to three years ago. Particularly in critical technology areas such as artificial intelligence, autonomous systems, cloud computing, and space-based surveillance and communications, Japan is lagging in international competition. Inefficient resource allocation that exclusively favors Japanese companies in these fields poses risks of increased costs, diminished capabilities, or both.

Challenges also remain in the operational mechanisms of the Japan-U.S. alliance. President Trump visited Japan at the end of October last year and reaffirmed the commitment to the security alliance. Secretary of Defense Pete Hegseth also made two favorable visits to Japan. However, behind the scenes, the mechanisms of the alliance are significantly slowing down. Since the inauguration of the Trump administration, Japan and the U.S. have not held a "2+2" meeting of foreign and defense ministers, and no future meetings have been announced. While practical-level meetings continue, without regular high-level engagement and the publication of a clear alliance agenda, there is a risk of stagnation.

Particularly important is the issue of the alliance's command structure. The U.S. Department of Defense is continuing efforts to upgrade the U.S. Forces Japan (USFJ) to a joint command and make it the true response agency for Japan's newly established Joint Operations Command (JJOC). This is a significant initiative announced under the Biden administration, confirmed by Secretary Hegseth. However, there remain significant questions regarding the day-to-day authority of the "new" USFJ and its relationship with the JJOC. Similarly, as Japan is set to begin operating long-range missile capabilities in 2026, the alliance has yet to develop a clear process for coordinating offensive operations. Addressing and resolving these issues requires actively engaged political leadership.

The situation in North Korea is also fluid. According to South Korea's National Intelligence Service (NIS), Kim Jong-un is believed to have intentions of making his approximately 13-year-old daughter, Kim Ju-ae, his successor. Since her public debut in November 2022, Kim Ju-ae has increasingly appeared in public, showing up ten times in 2023, twelve times in 2024, and fifteen times in 2025. According to the Asan Institute for Policy Studies, Japanese media reported that she has appeared publicly over 600 times since November 2022 based on facial recognition analysis. Her public activities have expanded from participation in military and economic events to include political and diplomatic events by 2025.

On February 9, Kim Jong-un announced during a visit to the Ministry of National Defense to commemorate the 78th anniversary of the Korean People's Army (KPA) that 2026 would be a "year of transformation" and that the KPA's front lines would "further expand." He stated that military capabilities would be "enhanced" over the next five years, adding that this is based on decisions to be announced at the 9th Party Congress. Notably, unlike the KPA commemorative speeches in 2024 and 2025, he did not mention the U.S. or South Korea.

According to assessments by the Stimson Center, of the 13 nuclear and conventional missile systems designated as development goals by North Korea at the 8th Party Congress in 2021, four systems are expected to be operationally deployed by 2026, with the possibility of two more becoming operational. North Korea has been expanding its efforts to diversify attack options, including the development of nuclear ballistic missile submarines capable of deploying submarine-launched ballistic missiles (SLBMs) from 2016 to 2025, improving survivability and accuracy.

These developments highlight the multilayered security challenges in Northeast Asia. Japan is advancing a historic strengthening of its defense capabilities but faces a triple challenge of financial constraints, political uncertainty, and delays in alliance coordination. The strengthening of support for North Korea by Russia and China is weakening the region's traditional deterrence structure and increasing the risk of nuclear proliferation. The U.S. shipbuilding cooperation plan may promote industrial integration among allies, but the unpredictability of the Trump administration's foreign policy poses serious concerns for Tokyo.

Particularly concerning is China's explicit and implicit threats and economic and military coercion against Japan, using Prime Minister Takaichi's remarks regarding the Taiwan Strait as a pretext. The Chinese Consul General in Osaka has even suggested that Prime Minister Takaichi should be beheaded. Such developments underscore the urgency of Japan's ambitious security reform agenda and the essential role of the Japan-U.S. alliance in regional peace, stability, and prosperity.

Prime Minister Takaichi's commitment to further strengthening national security and defense posture is important and should be welcomed. The formulation of Japan's next defense strategy and new five-year plan is already underway and is expected to be nearly completed by late 2026. As Japan addresses upcoming challenges, revitalized, close, high-level dialogue and a solid agenda regarding alliance priorities are essential and urgent.

The security environment in Northeast Asia is entering a period of structural change. Strengthening the Japan-U.S. alliance, deepening defense industrial cooperation, and effectively responding to the revisionist collaboration of China, Russia, and North Korea require strategic clarity and close coordination among allies. How Japan under the Takaichi administration addresses these challenges will significantly influence the trajectory of regional security in the coming years.