PARIS ― The Japanese and the British may seem very different, but a closer look reveals something akin to a parallel destiny for these two island peoples. With their old imperial ambitions and widespread distaste for the great continents from which the narrowest of seas divide them, both the British and the Japanese are vulnerable to the siren song of isolationism. Unfortunately, both now appear to be succumbing to that dangerous temptation.

Perhaps geography is destiny. As islanders, Britons and Japanese have had wary relations with ― and often a superiority complex toward ― their great continental neighbors, Europe and China, respectively. Both historically compensated for their isolation with strong central governments, powerful navies, dynamic entrepreneurship, vibrant culture, and imperial ambition.

Today, Japan and the United Kingdom pretend to be open societies, and to be stakeholders in the globalization process. In reality, both remain mostly inward looking and preoccupied with the disintegration of their original culture. Both try desperately to keep immigrants at bay, whether through cultural segregation in the U.K. or, in Japan’s case, by mere rejection. The more civilizations become intertwined in the new world order, the more the Japanese and British are tempted to remain aloof and apart.

In Japan, the isolationist temptation is expressed in the current nostalgia for the Edo period, from 1600 to 1868, before Emperor Meiji opened Japan to the world. “Back to Edo” has become a dominant mood and theme in public debates, promoted by writers, pundits, and historians like Inose Naoki (who is also vice governor of Tokyo), who argue that the Japanese were much happier within their closed world, blissfully insulated from the quest for material success and international status.

This “Back to Edo” discourse translates into the refusal of young Japanese to learn a foreign language or travel abroad. Indeed, in Europe, North America, and elsewhere, the omnipresent Japanese tourists of the 1970s have been replaced by Chinese and Koreans. The number of Japanese studying abroad is at a new low at the very moment when South Koreans and Chinese are swarming into European and North American universities. Even the world’s great universities, from Harvard to Oxford, are seeing fewer Japanese students.

Here the British are very much mimicking the Japanese: fewer and fewer are learning foreign languages, studying abroad, and following the old path of working in Hong Kong, Singapore, or Australia. So prevalent is this “little England” mood that Prime Minister David Cameron’s government is now tempted to hold a referendum to ask the British whether they want to remain within the European Union, a vote that even the arch euro-skeptic, Margaret Thatcher, never risked.

The prospect of a referendum reflects the overwhelming mood among the Tories, who sometimes mention Norway ― a non-EU member whose main role in global affairs is to award the Nobel Peace Prize ― as a model for Britain’s role in the world. Of course, Norway has the world’s highest per capita income. But that is not the relevant standard against which the U.K. or other Western countries should measure themselves, because Norway has a tiny, homogeneous, population and sits on vast ― and well-managed ― natural resources.

If asked in a referendum, the British might well leave the EU, which they never liked. This would have the unintended consequence of strengthening the federalists on the continent, thereby accelerating the integration dynamic that the British now want to stop.

Indeed, the British would leave just when Iceland, Serbia, Turkey, and Ukraine, despite Europe’s current crisis, are trying to get in. And, while the eurozone may be in crisis, Poland, among others, still want to join in the near future. The British may turn their nose up at the euro ― to which even the supposedly independent Swiss franc is pegged ― but it will almost certainly remain the currency of nearly 300 million Europeans.

Isolationism, whether in Japan or the U.K., is not only a short-sighted choice; especially for Japan, it may also be a perilous one, given the rise of China next door. Both Japan and the U.K., much as they may not wish to admit it, depend on the global market. Isolationism would leave their citizens ill prepared to confront competition and their governments excluded from decisions that impact the global economy and trade. Nor can isolationism guarantee national security at a time of rising threats from terrorist groups and rising ambitions on the part of China and Russia.

The Edo nostalgia in Japan and the Norway model’s appeal in the U.K. are not rational choices. They merely channel national wariness at a time of global competition between cultures, economies, and emerging strategic ambitions.

Sometimes nations, like individuals, grow tired and long for their idealized youth ― a recurrent phenomenon that historians call “declinism.” Whether one calls it that or a desire for a holiday from history, Japan and the U.K. today seem to be choosing a path that will only accelerate decline.

By Guy Sorman

Guy Sorman, a French philosopher and economist, is the author of “Economics Does Not Lie.” ― Ed.

(Project Syndicate)