Seventy-five years ago, major media outlets have reminded us over recent weeks, Franklin D. Roosevelt’s New Deal had its American debut. But when exactly did the New Deal end? The American Journal of Public Health has just published a fascinating article that suggests a surprising answer.

FDR’s New Dealers, the evidence in this piece by analysts Stephen Bezruchka, Tsukasa Namekata, and Maria Gilson Sistrom helps establish, may have actually scored their biggest victory over inequality after Roosevelt died in 1945. And this landmark victory didn’t even take place inside the United States. America’s New Dealers had their last—and most lasting—egalitarian hurrah in Japan.

Japan’s “New Deal” era began in 1945, right after the surrender that ended World War II. The public policy veterans of the Roosevelt administration who streamed into Japan that year, as staffers for the Allied Occupation run by General Douglas MacArthur, found not just a war-weary nation, but a deeply unequal one.

By 1952, the year the occupation ended, that gross inequality was fast disappearing. Japan would soon become one of the world’s most equal — and prosperous — nations. By the late 1980s, World Bank statistics document, Japan would sport the world’s smallest internal gaps in income distribution.

More Equality, Longer Lives

What’s an article about an economic story over half a century old doing in a professional health journal? The simple answer: Japan didn’t just become more equal after World War II. Japan became incredibly healthier.

In the half-century before World War II, a time when huge business conglomerates had come to concentrate Japan’s growing industrial wealth within a narrow privileged class, average Japanese men lived just 42.8 years. By 1960, male life expectancy had registered a remarkable rise to 60.8 years, and Japanese women had seen their lifespans increase, on average, from 51.1 years to 64.8.

The top U.S. health official during the Allied occupation of Japan, note Bezruchka and his colleagues, would later call this “astounding jump” in life expectancy “unequaled in any country in the world in medical history in a comparable period of time.”

Japan’s lifespan gains would continue. By 1979, no people in the entire world lived any longer than the Japanese. The world’s most equal and most healthy nations, in effect, had become one and the same.

A coincidence? Health analysts like Bezruchka, Namekata, and Sistrom don’t think so — and they strengthen their case for a link between inequality and health by exploring other possible explanations for Japan’s post-World War II gains in life expectancy.

The Japanese, the three authors show, didn’t become healthier because the Japanese health care system suddenly became world-class. It didn’t. And Japan didn’t jump to the top of the world lifespan rankings because Japanese families eat a wholesome Asian cuisine. Japanese eating habits have actually become more Westernized — and less healthy — since World War II.

Nor do individuals in Japan avoid unhealthy personal habits. Men in Japan smoke, for instance, at among the highest rates in the developed world.

So what’s behind Japan’s fabulously good health outcomes? Japan’s phenomenal health success reflects the importance of what analysts now call the “social determinants of health.”

“Policies that produce more egalitarian societies,” as the Bezruchka team puts it, “may explain profound health improvements.”

Political Changes Cut Stress

These improvements most likely work their medical magic by reducing debilitating chronic stress. And this stress reduction owes far more to “political changes” than to “specific public health programs.”

What “political changes”? The American occupiers of Japan came in committed to a set of priorities that would eventually be dubbed the “3 Ds”: the demilitarization of Japanese society, the democratization of the nation’s political process, and the decentralization of Japan’s wealth and power.

To ensure that decentralization, the occupation broke up Japan’s business empires, encouraged labor unions, implemented a mammoth land reform, and even legislated a maximum wage. American occupiers linked these policies to the cooperative spirit of Japan’s Confucian past and “unlocked,” in the process, indigenous social forces that continued to drive Japan in a more egalitarian direction long after the occupation ended.

“Japan’s good health status today is not primarily the result of individual health behaviors or the country’s health care system,” Bezruchka, Namekata, and Sistrom sum up. “Rather, it is the result of the continuing economic equality that is the legacy of dismantling the prewar hierarchy.”

In the United States, meanwhile, the New Deal drive to greater equality shifted into reverse in the 1970s and has been speeding backwards ever since. Americans have paid for that reversal. In 2004, according to United Nations data, the people of the United States ranked 30th in global life expectancy. The Japanese ranked first.

Disgruntled Elites

That ranking should have everyone in Japan cheering—and endeavoring to maintain the relative middle class equality responsible for Japan’s good health. But not everyone in Japan has been cheering. Japanese-style equality has fierce—and powerful—critics. Average Japanese families may enjoy a world-class quality of life. But Japan’s elites do not.

On the global stage, these elites have been losing ground. In the 1990s, top Japanese executives watched their American counterparts take home paychecks that tripled—and then tripled again—executive paychecks in Japanese corporations. Japan, the money crowd began to claim, no longer offered “the best and the brightest” enough of an incentive. The Japanese, business leaders insisted, needed to wake up to global realities. They couldn’t possibly expect to subject the rich to high taxes and still grow their economy.

In 2001, as Japan’s newly elected prime minister, Junichiro Koizumi would set about to make the sorts of changes business leaders were demanding. Those included privatizing Japan Post, the huge public agency that served both as Japan’s post office and national savings bank, and abolishing government restrictions that discouraged corporations from replacing full-time workers with temporaries. By 2006, the year Koizumi left office, the combined tax rate on income in Japan’s top tax bracket — 88% as recently as 1985 — had fallen to 50%.

Japan, the British newspaper The Independent reported earlier this year, “is becoming a two-tiered society.” One particularly glaring symbol of Japan’s growing gap: Tokyo currently hosts the most expensive restaurant in the world. At the Aragawa steakhouse, meals start at over $650 a plate.

Japan still remains considerably more equal than the United States, but the two nations now seem to be racing in the same direction. How long will the two continue to head down the road to ever greater inequality? For average Japanese and American families, the answer matters. Their health depends on it.