This article is part of Engelsberg Ideas’ latest series, ‘The Nuclear World Transformed’, in which our writers explore the history and current state of the global nuclear landscape, and how it is being reshaped by a new age of great-power competition.

It can’t be pleasant for European leaders to find themselves accused by Donald Trump’s administration of freeloading when it comes to their own defence, but they can take some small comfort in the knowledge that the Japanese have it worse. President Trump is in many ways a product of the 1980s, a decade in which Americans came to regard with a certain amount of bitterness the fact that Japan’s extraordinary wealth – its economy was the second-largest in the world back then – was built in no small part on American security guarantees. Rather than showing the appropriate gratitude, in 1989 alone Sony bought Columbia Pictures while Mitsubishi purchased a controlling stake in the Rockefeller Group. A few years later, during the first Gulf War, Japan contributed a hefty amount to proceedings – some $13 billion – only for some US critics to complain: ‘They pay in yen, we pay in blood.’

Fast forward to Trump’s first election campaign in 2016. While on the campaign trail in Iowa he told a rally: ‘You know, we have a treaty with Japan where if Japan is attacked, we have to use the full force and might of the United States. If we’re attacked, Japan doesn’t have to do anything. They can sit home and watch Sony television. What kind of deals are these?’ Trump has referenced this concern again during his second term, calling US-Japan security arrangements ‘one-sided’. The US wants Japan to raise its defence expenditure from around 1.8 per cent of GDP, currently, to three per cent.

In Japan, meanwhile, there has long been a fear that American security guarantees may not be as iron-clad as once they were. There is a risk that two trajectories coincide in the years to come, spelling danger for Japan: the steady rise of China’s capacities as a naval power and a steady fall in US public willingness to come to Taiwan’s aid should China try to take the island by force.

The seeds of this situation were sown 80 years ago when, a mere fortnight after Japan’s surrender in the Second World War, US General Douglas MacArthur touched down at Atsugi Airbase, near Tokyo. It was the beginning of a seven-year Allied Occupation of Japan, led by the United States and marking a momentous turn in Japan’s long history. Its effects are still felt today: in the mix of closeness and simmering mutual mistrust that characterises the US-Japan relationship; in the difficult relationships that exist between Japan, South Korea and China; and in Japan’s highly imperfect democracy.

Planning for an occupation of Japan began soon after the attack on Pearl Harbor, in December 1941. Those involved asked themselves what it was that had happened to Japan, after its opening up to the modern West in the 1850s and 1860s, which had caused it to take such a dark turn in the 1930s: towards militarism and aggression against its neighbours, both near and far. The answer, it was thought, could be summed up in two words: stunted growth. The Japanese had embraced all that the modern West had to offer, from new weapons technologies through to banking and postal systems, schools and universities, industry and commerce and even a limited form of democracy. Yet despite these changes, something deeper in the Japanese psyche had remained unchanged – unreformed. There lingered, American analysts suspected, a feudal mindset: relatively unquestioning of authority, insufficiently individualist, unconvinced of the virtues of democracy and of liberal civil society.

Critics in Japan regarded arguments like these as fundamentally flawed. They seemed to be based on a misreading of Japanese wartime propaganda – deeply chauvinistic and anti-western – as accurately reflective of ordinary public sentiment and psychology. But some agreed with the American assessment, at least in part. The celebrated Japanese political scientist Maruyama Masao called for a new balance of self-sufficiency with public commitment, the latter dutifully rather than slavishly pursued. Others in Japan began to use the phrase ‘dark valley’ to describe what their country had passed through in the 1930s and 1940s, emphasising that the period was a tragic deviation from a civilised, democratic norm, to which Japan was well capable of returning.

Armed with their far-reaching analysis of Japan’s recent past, large numbers of young and idealistic American men and women joined the Occupation and helped to oversee the ‘Three Ds’ that stood at its heart. Japan had to be demilitarised. Power had to be decentralised: the cosy old arrangements whereby big conglomerates controlled huge swathes of the economy and their top personnel sometimes intermarried with civil service families had to be done away with. And, finally, democratisation: women should have the vote, elected representatives should hold ultimate power, and all Japanese should feel as though their voices truly mattered in national and local government alike.

Three years into the Occupation, much of this had been achieved. Japan’s empire had been dismantled and its armed forces disbanded. It had become the first country in history to have a new constitution authored by a foreign power. The US insisted on a ‘pacifist clause’, forbidding Japan from maintaining the means to wage war. The first elections had taken place, on the expanded franchise. Socialists and Communists had been released from jail and allowed to compete for parliamentary seats. Trades unions were permitted once again. Ambitious land redistribution had turned millions of tenants into owner-farmers. And some 200,000 people with links to the old regime – journalists, teachers, publishers, policemen and military officers – had been purged from public life.

A small number of suspected war criminals had been tried in Tokyo at Japan’s equivalent of the Nuremberg Trials. Twenty-five defendants were each found guilty on at least one count. Seven, including former Prime Minister Tōjō Hideki, were sentenced to death. The Emperor had feared that he too might end up in the dock. The awful idea presented itself that the Japanese imperial line, stretching back to the 500s and perhaps further, might end with a man swinging by his neck from a hangman’s rope. But MacArthur and the Allies let Hirohito live, insisting only that he publicly renounce the old imperial claim to be a ‘manifest kami’ (god) and consent to being a symbol of the nation rather than enjoying any commanding authority. Hirohito was also made to suffer the indignity of being photographed with MacArthur looming tall and proud over him – an iconic image of the Occupation, which a deeply embarrassed Japanese government tried, unsuccessfully, to have banned.

Most of the early Occupation reforms met with general approval in Japan, albeit that occasionally Occupation personnel could be a little over-zealous in trying to change Japanese hearts and minds. Cartoonists were forbidden from creating caricatures of MacArthur. A haiku that ran ‘Small green vegetables / are growing in the rain / along the burned street’ was banned, as ‘Criticism of the United States’. Painters were steered away from depicting the distinctive torii gateways to Shinto shrines, because of their nationalist resonance. And having had one of his films, They Who Step on the Tiger’s Tail, banned during the war for being ‘too democratic’, director Akira Kurosawa had to put up with seeing the same film now banned for being ‘too feudal’.

Then something unexpected happened. The view from America began to change, especially among conservatives. Relations with the Soviets were deteriorating and Asia looked like a place where, with Soviet support, Communism might do disturbingly well for itself – especially after the long-feared Communist Revolution happened in China, in October 1949. The US, more than ever, found itself in need of a reliable Asian ally – and Japan fitted the bill. The result was what became known as the ‘reverse course’: a decisive rightward shift in the Occupation, as part of which trades unions were clamped down on, leftist influences in public life were purged, and plans were laid for a ‘National Police Reserve’.

This last was something of a euphemism. Until 1950, security and public order in Japan was ultimately the business of US armed forces. The early years of the Occupation had been a lot less bloody than some had feared – the anticipated attempts to attack or even overthrow the Occupation regime had not transpired, although some former Japanese army officers had stockpiled weapons and cash for just such a venture. That being so, a great many of the soldiers sent to Japan were soon moved on elsewhere. Then, in 1950, Kim Il-sung’s Korean People’s Army surged down over the 38th parallel dividing North from South Korea. A freshly-formed United Nations arranged a force for South Korea’s defence and MacArthur was selected to lead it. A great many of the US soldiers in Japan at the time were called up to serve in the war, hence the formation of a Japanese ‘National Police Reserve’ (NPR) to look after domestic security while they were away.

Plenty of people in Japan were unhappy about this. They remembered the Special Higher Police and the Kempetai military police from just a few years earlier: both had spied on the population, conducted raids, imprisoned people without charge and resorted to torture to get what they wanted. The NPR looked like the beginning of a drift back to those bad old days. Japan’s former enemies were also unhappy. They rightly suspected that the US intended for the NPR to become the nucleus of a future Japanese army – and indeed it would have been an impressive domestic insurrection whose quelling required the use of bazookas, flame-throwers, mortars, tanks and artillery.

Another important part of the reverse course involved rescuing Japan from becoming what some in the US feared would be a Communist basket-case. The hope, instead, was to create a nation of reliably centre-right and US-friendly politicians, hard workers and successful companies, with whom US firms might do some lucrative business. Rumours have persisted for years that Japanese yakuza (gangsters) and America’s CIA played an outsized role in achieving this goal, helping to organise and bankroll a new Liberal Democratic Party in 1955. A political behemoth forged from a coalition of conservative parties, it has rarely been out of power in Japan since it was created.

At the same time, the aim of economic decentralisation was quietly allowed to slip away. Instead, former zaibatsu – conglomerates like Mitsubishi, with historically close ties to politicians and bureaucrats – were permitted to make a comeback. Japanese businesses did well out of the Korean War, fielding large orders from the US military for supplies (worth around $800 million a year and causing Japan’s Prime Minister, Yoshida Shigeru, to offer up thanks for a ‘gift from the gods’). One of the jobs, meanwhile, of Japan’s Ministry for International Trade and Industry (MITI) was to help co-ordinate between business, banks and politicians, so that scarce capital could be ploughed into the industries of the future – notably electronics and automobiles.

One of the eventual beneficiaries of all this was an Occupation-era start-up called Tokyo Telecommunications Engineering Company. It began life trying to sell 35-kilogram tape recorders, before MITI belatedly allowed it to purchase the manufacturing license in Japan for a new invention called a ‘transistor’. It soon downsized both its products and its branding, coming up with a pocket-sized radio and calling itself ‘Sony’ – after the word ‘sonny-boy,’ beloved of American GIs serving in Japan. Beyond technology, the US contribution to success stories like Sony included favourable dollar-yen exchange rates and import regimes, alongside the chaperoning of Japan back into polite international society – Japan joined the International Monetary Fund and World Bank in 1952, and the United Nations in 1956.

The US-Japan security relationship, whose outlines emerged as part of the reverse course, was controversial right from the start. The Soviet Union refused to sign the San Francisco Peace Treaty of 1951, between Japan and its former enemies, because it objected to the US-Japan Security Treaty that was signed at the same time. This effectively turned the Japanese archipelago into an enormous US aircraft carrier. The United States was permitted to retain military bases on Japanese soil, including tens of thousands of soldiers. It maintained an especially heavy presence in Okinawa, which remained in American hands even when the Occupation ended the following year, in 1952.

What this meant, feared pacifist critics in Japan, was that having dropped two atomic bombs on their country during the Second World War, the United States was now putting Japan in the firing line for Soviet nuclear weapons – under rapid development by this point, following a first successful nuclear test in 1949. The presence of large numbers of American soldiers in and around US bases meanwhile seemed to drive an increase in prostitution and violence, while American music risked corrupting the young of Japan with its (by Japanese standards) highly sexualised lyrics.

More broadly, Japanese conservatives worried that the US had effectively followed up its military victory in 1945 with a culture war. New rules on divorce and property rights threatened the old-style patriarchal Japanese household. School textbooks seemed to educate children into feeling guilty about their country’s past misdeeds while offering little by way of patriotic content. And from rockabilly to TV gameshows, American popular culture was beginning to dominate Japan’s mass media.

One final major legacy of the Occupation emerged from a combination of the limited nature of the war crimes trials and the effective take-over of Japanese foreign policy by the United States. Given the exceptionally bloody war that Japan had inflicted on China, beginning in 1931, the future of East Asia depended in large part on these two countries finding some way of accommodating one another in the postwar world. That was made more difficult by the victory of the Chinese Communist Party in China’s civil war, both for its resolutely anti-Japanese and anti-imperial credentials and because the United States wanted its Japanese ally to have nothing to do with China’s communists.

Bridge-building opportunities with China were largely lost until the 1970s as a result, made worse by the fact that, as the Chinese judge at the Tokyo war crimes trials Mei Ju-ao remarked, the United States seemed to have pursued a scapegoat strategy: limiting war responsibility to a small ‘group of evil culprits’, in the hope of recruiting everyone else to help build a new Japan. Scant justice was done, as a result, to many of the crimes that mattered to the Chinese population – not least the Nanjing Massacre, few of whose victims could afford to attend the trials in person in order to give evidence.

The perception emerged, and has never really gone away, that whereas West Germany put itself through an agonising but necessary period of post-Nazi reflection, the Japanese were allergic to talk of the war and to the requirement for taking responsibility and making meaningful apology. The security provided by the US-Japan alliance took some of the urgency out of all this: as long as Japan was safe and prosperous, it could look across the Pacific and focus its friendships on the US and the western democracies, rather than carving out a new role for itself in East Asia.

These arrangements, which contributed to stunning economic growth in Japan across the late 1950s and 1960s – more than 10 per cent every year, on average – began to come apart from the 1970s onwards. First, President Richard Nixon decided to seek rapprochement with China, allowing Japan belatedly to do the same. Then, in the 1990s, the usefulness of Japan to the US in a post-Cold War world became increasingly unclear. This was followed, from the 2000s, by concerns about whether the US was capable of defending Japan, even if it wanted to. How had its intelligence services failed to thwart the 9/11 attackers? Why was it so incapable of getting its way in Afghanistan and Iraq? Why didn’t it have a credible plan to contain China in the Asia-Pacific? Compounding all this was that sense of American resentment, seen most clearly in the electronics and automobile sectors, that its generosity in setting Japan back on its feet after the war had been repaid by a form of economic warfare.

Eighty years on from the start of the Occupation, the US-Japan relationship looks as though it could go one of two ways. Perhaps the United States will decide to double down on its commitment to Japan, as its best hope of countering China. This will likely involve constant pressure on the Japanese to spend more on their military and to steadily set aside their postwar commitment to pacificism. They will be encouraged to learn to love their euphemistically-named ‘Self-Defence Forces’ (successors to the NPR) and to permit them first-strike capabilities – currently a controversial idea, which Japan’s constitution appears to forbid.

The other possibility is that some combination of partial US withdrawal from the Asia-Pacific with a more amenable regime in China, under whoever succeeds Xi Jinping, may encourage the Japanese to redouble their efforts in achieving what largely eluded them during the Occupation: the forging of real, lasting friendships with their near-neighbours in East Asia. Deeper co-operation with China is not impossible, covering the kinds of 21st-century challenges that defy borders: climate change, ageing and shrinking populations (a problem for China and Japan alike) and, of course, artificial intelligence.

We must hope, however unlikely it may seem, that Japan can go another 80 years without becoming embroiled in a major war. Whatever happens, it is clear in retrospect that the Occupation helped Japan to avoid the kind of chaos and resentment that might have encouraged a rapid return to chauvinistic authoritarianism, propelling it into fresh conflict long before now. Those seven years were, if not quite a ‘gift from the gods’, then far from the worst thing that might have greeted the Japanese as they emerged from their dark valley of militarism and war.