A decade or so from now, people may look back on 2019 as a turning point for Japan – the moment it finally came to terms with its own security in the 21st century.

Two years of the Donald Trump administration in the United States have shaken the Japanese public, but after a bit of shock, they have accepted a new reality. This is a post-Iraq-war world and Japan, for the first time since the end of the second world war, is facing the challenge of providing for its own security.

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In the quarter century since the end of the cold war, which did not conclude with a “peace dividend” for East Asia, Japan has had to cope with the changing times. Throughout the 1990s, its alliance with the US was redefined, and Tokyo has had to confirm that such an alliance is still relevant. It has also sought to normalise its security policy while continuing its pacifist tradition. The ability to send its Self Defence Forces to peace missions overseas, and exercise collective self-defence with the US, were important steps during this period.

But Japan is now facing the sobering reality that its security environment has changed, more so than the incremental steps it has so far taken towards bolstering its defences would suggest.

Asia has faced its fair share of security challenges in the past – from the Soviet military build-up of the 1950s and 1960s, to China becoming a nuclear power in 1964 and the North Korean nuclear crisis that still rumbles on to this day – but none of these crises changed the fundamentals of East Asian security, since the US’ relative military superiority and resolve were never in question.

So long as the region could count on US commitment, other factors were of secondary concern.

What has changed in the Trump era is American resolve. His emergence within the Republican Party, mirrored on the left by a renewed enthusiasm for disengagement within the Democratic Party, is a clear sign of shifting priorities in the US over whether to maintain its informal “empire” overseas.

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Of course, America will not simply turn over its worldwide dominance to China. Its recent focus on pressuring China economically, and rebuilding its technological pre-eminence, are clear signs that it doesn’t intend to do so. From a security perspective, the US’ modernisation of its nuclear arsenal, investments in artificial intelligence and cybersecurity, and honing in on space warfare are all signs of its imperial resolve. But that doesn’t necessarily translate into regional hegemony in East Asia.

Talks between the US and North Korea have also signalled a symbolic change to US foreign policy in the region.

US appeasement towards Pyongyang has been met by feelings of disappointment and helplessness in the Japanese media, especially when Trump mentioned Japan as one of the main cost bearers of denuclearisation, despite no concrete agreement having been made. Once again, Japan would be paying for something it has little influence over.

The country finds itself in an awkward position, as it has no offensive capabilities to draw concessions out of North Korea, yet the US does not share its fear of Pyongyang. Tokyo can only attempt to influence the situation by influencing the US.

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The talks have also exposed a more fundamental issue: the gap in perceptions between Tokyo and Washington regarding their alliance. The Trump administration embodies a distrust of Japan as a “free-rider” that does not contribute enough towards its own defence. This is not a view widely shared in Japan at all. The Japanese public is more afraid of “entrapment” by the US and becoming tangled up in its wars. This perception gap exists because the Japanese public have largely been shielded from the realities of the alliance by a government that has feared being abandoned by the US, but did not want to broadcast its hospitality towards the superpower for fear of a pacifist backlash.

In the two years since Trump came to power, the Japanese public have become increasingly sceptical of US support in the case of a limited crisis, such as one involving the disputed Diaoyu Islands, which Japan calls the Senkaku Islands. Japanese progressives – both in opposition and in the media – have become more isolationist. They are keen to weaken the alliance, but not necessarily build up independent military capabilities. Neither do recent progressives see China favourably, compared with the cold war period.

In the same way Japan is wary of the US, it is also wary of South Korea given their historical issues, with ties fraying again now because of a disagreement over wartime labour compensation.

The conservatives in power, meanwhile, are gradually adapting to a new reality. Japan has reinforced its military relationships with others, such as the members of the Quad, and plans to boost defence spending over the next five years with advanced military equipment from the US.

Yet these guidelines, while championing resilience and self-sustainability, also continue with the basic philosophy of pacifism. The remaining years of the Trump era are likely to see Japanese society further torn between isolationism and realism.

Lully Miura is a lecturer at the Policy Alternatives Research Institute of the University of Tokyo