Many people in the world were at least vaguely apprehensive that the birth of the second Trump administration would be a major challenge to the international order. Now, with the speed and intensity of a speeded-up video, the international order that has been built since World War II is collapsing. The world is seeing the reality that when a destroyer sits in the driver's seat of the U.S., which has so far sustained order, the destruction proceeds beyond expectations.

Japan clearly recognises this shift in the international order and is considering its future strategy. What shocked the world when Trump abandoned his position of defending the international order and instead stood on the side of the revisionists was the U.S. vote at the UN General Assembly on 24 February 2025. On that day, three full years after Russia's invasion of Ukraine, the UN held a special session and with a majority of 93 countries adopted a resolution in which European nations condemned Russian aggression and supported Ukraine's territorial integrity. The U.S. voted against the resolution, along with Russia and 17 other countries¹.

According to someone who was there, the U.S. vote shocked the audience, as if the sky and the earth were turned upside down. Even though a compromise with Russia was necessary to end the war in Ukraine, the Trump administration's action in opposing a resolution by its European allies condemning Russia's war in Ukraine, which clashed with the UN Charter and humanity, was a dramatic departure of the US position from its previous stance as defender of the post-World War II international order.

Nevertheless, due to the Trump administration's continued tough stance against China, Japan was less shocked by the U.S. vote than its European allies, as it did not diminish its value as a frontline ally against China. On the other hand, the war in Ukraine has raised concerns in Japan about the ongoing military cooperation between China and Russia, and also between North Korea and Russia. In this context, a decline in the U.S. commitment to NATO is bad news for Japan. This is because although there are ‘prioritisers’ in the second Trump administration who prioritise competition with China over the security of the Middle East and Europe, many members of the Trump administration are ‘restrainers,’ including President Trump and Vice President Vance, who seek to reduce U.S. security engagement all over the world².

In this international situation, Japan is strengthening its own defence capabilities and expanding its role in the Japan-U.S. alliance as a hedge against declining U.S. involvement. In addition, Japan is promoting closer security cooperative relations with U.S. allies in the Indo-Pacific and Europe. The so-called ‘America After Trump’ project of the Sasakawa Peace Foundation, which the author participates in, calls this strategy ‘Plan A+’ and is preparing policy recommendations. This paper introduces Japan's ‘Plan A+’ strategy and shows that cooperation with Europe is an important pillar of its foreign policy.

On 2 April the Trump administration imposed additional tariffs on all countries with a flat 10% tariff plus a reciprocal tariff in a formula that aimed to cut down trade surpluses vis-à-vis the U.S.³ The administration decided to impose ‘reciprocal tariffs’ on its allies the EU (20%), Japan (24%) and South Korea (25%), and while it imposed a 34% tariff on rival China, it imposed tariffs on fellow rivals Iran (10%) and Venezuela (15%) that were lower than those on its allies.⁴

In response to the decision, China and others launched countermeasures, and the markets predicted a recession resulting from the trade war that engulfed the world and sent global stock prices plummeting. On 6 April, President Trump defended his tariff measures stating "I don't want anything to go down, but sometimes you have to take medicine to fix something" and "We have been treated so badly by other countries because we had stupid leadership that allowed this to happen.”⁵

Trump's logic is to bring manufacturing back to the U.S. by imposing harsh tariffs on allies who have enjoyed economic prosperity as free riders on the US open market with asymmetrical tariffs and non-tariff barriers. The onshoring of manufacturing capacity will enrich struggling U.S. workers left behind the constant U.S. economic growth in service sectors, which benefited from economic globalisation.⁶ At the time of writing, no one knows how the tariffs will ultimately settle down, as Trump has suspended enforcement of the extra tariffs except the universal 10% tariff and the universal 25% tariffs on steel, aluminium and automobiles for 90 days to lessen the damage to his own economy, and he is continuing negotiations with other countries.⁷

What is clear, however, is that the post-World War II strategic view that U.S. leaders have shared so far is changing dramatically in the wake of Trump's reemergence. Trump's America does not believe that protecting its allies is in the U.S. interest but rather that it is a liability.

This has a certain rationale in the U.S. because of enthusiastic support by the MAGA (Make America Great Again) movement backing Trump. The U.S. developed its grand strategy in the Cold War after World War II to fight and win against the Soviet Union, China and the communist camp. The U.S. created and led a liberal bloc against the Soviet communist bloc, which managed a command economy that was less efficient than the liberal economy, and the U.S. gave nations in the liberal bloc opportunities for economic growth by signing security treaties and providing military assistance. At the same time, the U.S. opened its markets to guarantee market access and provide opportunities for economic growth. It also cut off China, which had joined the communist bloc, but eventually from the 1970s gave it access to the U.S. market to grow its economy and compete with the Soviet Union, which led to a stalemate in the Soviet communist bloc's economy and the collapse of the Soviet Union without a major war.

It was Japan and Europe that took advantage of this situation to rise from the depths of war-devastated exhaustion to become economic powers after the second world war. Japan's strategy of relying on the United States for defence and concentrating resources on economic growth became known as the ‘Yoshida Doctrine,’ named after Prime Minister Shigeru Yoshida, who was often compared to West German Chancellor Adenauer in a similar role.⁸

Japan's heightened economic competitiveness threatened U.S. economic primacy from the 1970s to the 1990s, and there was U.S.-Japan trade friction, but Japan used this experience to expand its role in the alliance with the United States and make it more important in both economic and security terms. For some US security and military experts, Japan is still regarded as a critical partner to counter China, a more formidable rival than Japan both economically and security-wise.⁹

However, it has become clear that the ‘Yoshida Doctrine’ will not work for Trump's America. Japan needs to become more independent, both economically and in terms of security. At the same time, this does not mean a confrontation or a break with the U.S. While maintaining an alliance with the U.S., which remains wary of China, the strategy will be to reduce Japan's excessive dependence on the U.S. in security and economics, where it could be forced to make unilateral concessions through the imposition of tariffs or other measures, such as unreasonably expensive security support.¹⁰

In order to achieve this aim, Japan will need more military power than ever before and cutting-edge technology to support its military and economy. In part to counter China, the Trump administration would require Japan to spend more on defence than it does now. Japan’s strategic move should be to make this a negotiated condition to protect the Japanese economy from tariffs, and the new defence budget will need to be invested in R&D for military and civilian technologies that will seed future economic growth.

On 23 May 2022, Chinese and Russian military aircraft conducted joint exercises at the same time as a Japan-U.S.-Australia-India (Quad) summit in Tokyo. Russian Tu-95 and Chinese Xi'an H-6 strategic bombers participated in a 13-hour exercise over the Sea of Japan and the East China Sea, and the Russian Defence Ministry announced that it had conducted a joint exercise with the Chinese military to patrol the Asia-Pacific region.¹¹ Since the first patrol in 2019, China and Russia have conducted strategic bomber joint air patrols around Japan and Taiwan eight times – in July 2019, December 2020, November 2021, May and November 2022, June and November 2023 and November 2024 – and they have become the norm.¹² As fighting between Ukraine and Russia continues and tensions between the U.S. and China over Taiwan increase, Japan must be wary not only of China but also of China-Russia collaboration.

On 10 February 2024, Trump revealed that he had said to NATO leaders that if they did not pay the money they owed for the military alliance, he would “encourage” Russia “to do whatever the hell they want” to them.¹³ Trump's re-election to the presidency in the November election is a reflection of the fact that Trump and his supporters do not see any benefit in alliances and allies.

Former President Biden delivered a televised address from the White House to the American people on 6 December 2023 regarding a supplementary budget for aid to Ukraine, on which the Republican House of Representatives took a negative stance. In this address, President Biden asked "And think, if we don’t support Ukraine, what’s the rest of the world going to do? What’s Japan going to do, which is supporting Ukraine now? What’s going to happen in terms of the G7? What’s going to happen in terms of our NATO Allies?”¹⁴

There is a reason why President Biden was the first to mention Japan in the context of support for Ukraine. Former Prime Minister Kishida actively supported Ukraine from the beginning of Russia's invasion, and he surprised Ukrainian President Zelensky by inviting him to the Hiroshima G7 in May 2023, where they both laid flowers at the Cenotaph for the Atomic Bomb Victims in Hiroshima. This was a message to Russian President Vladimir Putin, who had occasionally suggested the use of nuclear weapons in the war in Ukraine, because President Biden had a strong impression of Prime Minister Kishida's diplomacy. In addition, Japan's active support for Ukraine in the face of China may have been a clear refutation¹⁵ of the rhetoric of Trump supporters in the U.S. that the real threat to the U.S. was China and that it could not afford to support Ukraine.

In three security documents approved by the Cabinet in December 2022, Japan set forth a more active defence of itself and a security assurance to the Indo-Pacific region. In addition to its own defence and strengthening its alliance with the U.S., the documents also strongly advocate security cooperation with key regional actors, namely Europe, India and ASEAN. Japan’s national security strategy document explicitly stated that as part of "maintaining and developing a free and open international order and strengthening cooperation with allies, comrades and other countries, Japan will build a multilayered network among allies and comrades,” while expanding and strengthening its deterrence capabilities. To this end, while utilising the Japan-U.S.-ROK and Japan-U.S.-Australia frameworks, Japan will develop cooperation with Australia, India, South Korea, ASEAN (the Association of Southeast Asian Nations), Canada, NATO and the European Union.¹⁶

Japan was greatly threatened by the strengthening of Sino-Russian ties, but it contributed to support for Ukraine and also promoted cooperation with European NATO members and U.S. allies in the Indo-Pacific – Australia, South Korea and the Philippines – to ensure its own survival and to maintain the international order. This was also a hedging strategy to cope with drastic changes in the world caused by Biden’s weakening influence and Trump’s potential re-emergence with his disengagement in international security, which has been a matter of concern since then. This was the prototype of the ‘Plan A+’ strategy that Japan should adopt in the future.

In past discussions of Japan's diplomatic and security strategy, the Plan A (based on the Japan-U.S. alliance) and the Plan B (substituting the Japan-U.S. alliance with cooperation with the United Nations, China and the Soviet Union) were compared and discussed as options.¹⁷ This was at the heart of diplomatic and security discussions during the Cold War.¹⁸ However, now that the UN has become dysfunctional and the appeal of socialist ideology has faded, Plan B has lost its rationality as a realistic option. On the other hand, simply adopting the status quo Plan A is not a reliable option to protect Japan's independence and prosperity considering the future relative decline of U.S. power, which would result in a weakened international order.

The direction of Japan's future foreign policy strategy, as proposed by the Sasakawa Peace Foundation's ‘America after Trump’ project, is a Plan A+ strategy. In short, in addition to Plan A, Japan will strengthen its own defence capabilities and deepen its cooperation with other U.S. allies and partners in the Indo-Pacific and Europe. In addition to the Japan-U.S. alliance, Japan should strengthen its own defence capability by introducing mid-range missiles such as U.S.-made Tomahawks and developing Japan’s indigenous longer-range missiles. Japan should deepen its horizontal cooperation with other U.S. allies and partners, such as Quad (Japan-U.S.-Australia-India) cooperation and Japan-NATO cooperation.

President Trump's America First policy suggests reducing America’s international military involvement, but at the same time Trump's position that U.S. allies are not bearing a commensurate burden compared to the excessive burden on the U.S. does not necessarily mean ‘isolationism’ in which the U.S. withdraws from all global involvement. Although nobody knows Trump’s ultimate aim, at least we can assume that he would brag of his great achievement if the U.S. allies bore a reasonable financial burden.¹⁹

Given the current situation, Plan B, in which Japan easily abandons the Japan-U.S. alliance, is premature. It would be more strategic to strengthen its own defence capabilities and reduce the burden on the U.S. for regional stability. This would effectively appeal to the U.S. with more in-depth cooperation with NATO members and EU countries, which are U.S. allies in Europe that share a similar awareness of the problem. This is because U.S. restrainers want relief from the heavy burden in the Middle East, in Europe and in the Indo-Pacific. This is why cooperation with Europe is one of the pillars of Plan A+.

In July 2023 Japan agreed to the Japan-NATO Individually Tailored Partnership Programme (ITPP), which includes enhanced responses to cyberattacks and artificial intelligence (AI).²⁰ On 9 April 2025, after the formation of the second Trump administration, Prime Minister Shigeru Ishiba and NATO Secretary General Rutte met in Japan and confirmed a policy of working to create a standard for ammunition and equipment used by Japan’s Self-Defence Forces and NATO member countries' militaries by matching component sizes and establishing a system to facilitate interchange in the United States and Europe to address global equipment shortages.²¹

Security cooperation between Europe and Japan has only just begun, but the uncertain future of the U.S., in addition to the threat from China and Russia, has undoubtedly increased the value of cooperation between them.

Therefore Plan A+ is being steadily implemented. U.S. historian Walter Russell Mead, quoting Hiroyuki Akita, a participant in the Sasakawa Peace Foundation's ‘America After Trump’ project and a Nikkei commentator who discussed the concept, wrote a response. Mead wrote that with challengers such as China, Russia and Iran undermining the stability of the U.S.-led order and the U.S. itself becoming less reliable and predictable than in the past, Plan A alone is no longer sufficient. The response of most of the U.S. allies has been to move to what Akita calls a ‘Plan A+’ posture. The allies want the U.S.-led order to remain intact, but they have realised that they must act more aggressively to compensate for what they perceive as U.S. weaknesses. He wrote that "countries that choose Plan A+ are tightening their relations with the U.S., increasing defence spending and intensifying efforts to strengthen the network of alliances that underpin the world order.” He sees this move as beneficial to the U.S. and states that “Americans are rightly pleased by the tendency of so many of our allies to go to Plan A+” while “it attests to the value that these countries place on the world order Americans have built, and we need all the help we can get in this dangerous time.” He also optimistically expects that “greater efforts from allies will also help American politicians persuade sceptical voters to continue their support for American global strategy.” ²²

Indeed, Japan's Plan A+ responds to complaints by President Trump and MAGA supporters that the U.S. bears an unduly heavy burden in maintaining the international order, while at the same time by actively participating in the formation of the international order Japan can remove complaints by Japanese domestic nationalists that it might otherwise be a protectorate of the U.S.

It would be a great crisis moment with a great chance for Japan and Europe to maintain the existing world order with closer security cooperation with strategic direction such as Plan A+. Japan and NATO have agreed on cooperation in the field of strategic communication and they share best practices on countering hybrid activities, including hostile information.²³ For future cooperation on a Taiwan contingency, some may think Europeans are located too far from a war theatre in East Asia. However, European military and intelligence capabilities could assist Taiwan and the U.S. and Japan with cyber and space capability “where geography does not impose limitations,” for example by contributing cyber and space capabilities, according to a US thinktank CNAS report entitled ‘Regional and Global Responses to a Taiwan Contingency.’ ²⁴