In recent years, as security tensions in the Indo-Pacific region continue to rise, the U.S.-Japan alliance has been gaining increasing weight in the regional strategic landscape. From tensions in the Taiwan Strait to military frictions in the East China Sea, and changes in Japan’s domestic political forces, multiple factors are pushing Washington and Tokyo to accelerate coordination on China policy. U.S. public opinion generally believes that, in the context of Trump’s second term, U.S.-Japan relations are entering a new phase marked by greater security and geopolitical significance.
Rising tensions in the Taiwan and East China Seas elevate regional security risks
China’s large-scale military actions around Taiwan in recent years have become a key indicator of rapid changes in the Indo-Pacific security environment. According to The Hill, a series of exercises named “Justice Mission 2025” included long-range live-fire drills, which Beijing described as a warning against “Taiwan independence separatists and external interference forces.” Many international observers believe these actions have pushed the Taiwan Strait situation to levels of tension rarely seen since the end of the Cold War.
Regional tensions have also spread to the East China Sea. Japan’s Ministry of Defense reported that Chinese aircraft once locked onto Japanese aircraft with radar in international waters southeast of Okinawa. In another incident, Chinese fighter jets tracked Japanese F-15s for about 30 minutes, considered one of the most serious direct military confrontations between China and Japan in over a decade.
Japanese Defense Minister Shinjiro Koizumi expressed “extreme regret,” lodged a stern protest with China, and strengthened coordination with U.S. allies, including Pete Hegseth. Security analysts widely believe these military interactions indicate that China-Japan relations face higher-risk strategic friction.
Japan’s security strategy shifts to strengthen Indo-Pacific deterrence
Facing growing security pressure, Japan has accelerated adjustments to its defense policy in recent years. The U.S. conservative media outlet National Review noted that Japan is expanding its military scale and capabilities, marking a significant turning point from its post-World War II pacifist security path.
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Tokyo continues to advance the “Free and Open Indo-Pacific” strategy, first proposed by the late Prime Minister Shinzo Abe, emphasizing freedom of navigation, regional stability, and a rules-based order. Current Prime Minister Sanae Takaichi seeks to deepen security cooperation and strengthen regional partnerships based on this framework.
Japan has recently relaxed restrictions on defense equipment exports and accelerated military modernization. For example, the U.S. approved the sale of long-range Tomahawk missiles to Japan, while Japan is advancing construction of Mogami-class frigates and plans to participate in regional defense cooperation projects. Security think tanks generally believe these measures will enhance the alliance’s overall deterrence capability.
U.S. strategic documents also regard the Indo-Pacific as a core global competition zone. Data show the region accounts for about 60 percent of global GDP and maritime trade, meaning instability there could disrupt global supply chains and economic stability.
Pace of US support for Japan draws attention
Despite deepening strategic cooperation, the pace of U.S. responses to certain regional crises has drawn external attention. In November last year, Takaichi stated that if China took military action against Taiwan involving force, it could constitute a “survival threat situation,” and the Japanese government would determine its response based on the circumstances.
China subsequently expressed strong dissatisfaction and escalated military actions. Weeks later, U.S. Ambassador to Japan George Glass publicly affirmed that the U.S. government “firmly supports” Japan. Meanwhile, Japanese Ambassador to the U.S. Shigeo Yamada had called for Washington to strengthen public support.
Following this, the U.S. and Japan conducted joint military exercises as a deterrence signal. Two U.S. B-52H strategic bombers and Japanese Air Self-Defense Force F-15J and F-35A aircraft conducted joint drills over the Sea of Japan. The two sides said the exercise aimed to strengthen alliance deterrence and rapid response capabilities.
Some international relations scholars note that the U.S. maintains a policy balance between trade negotiations and regional security, resulting in relatively cautious public statements, but military coordination still demonstrates that the alliance remains solid.
Stable Japanese politics provides support for alliance deepening
Japan’s domestic political landscape has also seen significant changes. NHK data show that Takaichi’s Liberal Democratic Party won 316 seats in the House of Representatives, achieving a supermajority of over two-thirds—a rare postwar record.
Trump publicly congratulated Takaichi and praised her policy direction of “maintaining peace through strength.” Takaichi responded that she looks forward to closer cooperation with Trump to further deepen Japan-U.S. relations.
Analysts note that Takaichi is considered one of Japan’s more pro-American leaders. From Shinzo Abe to Shigeru Ishiba, and now Takaichi, Japan’s conservative political forces have long maintained communication channels with the Trump administration. In a context where some traditional allies’ relations with the U.S. are fluctuating, the stability of U.S.-Japan relations has drawn more attention.
Reshaping the Indo-Pacific strategic landscape makes alliance coordination key
Many think tanks believe China’s continued military buildup and intensified pressure on Taiwan are key drivers of changes in the Indo-Pacific security structure. Meanwhile, North Korea’s nuclear development continues to pose a regional security challenge, making Japan a frontline state in geopolitical security.
International strategic observers generally agree that, in the face of escalating geopolitical competition, the U.S. and its allies need to strengthen defense and economic coordination to build a more credible collective security system. With Japan’s growing military capabilities and domestic political support, the U.S.-Japan alliance is gradually shifting from a traditional defensive framework to a more proactive strategic collaboration model.