Peter Popham: The Arab Spring has had no effect on a country immune to outside influences

Even more than the US invasions of Afghanistan and Iraq, the Arab Spring has sent shivers of fear through the world's despots. Muammar Gaddafi has come and gone. Bashar al-Assad has slaughtered his way into a bloody cul-de-sac. The kleptocratic Burmese generals, masquerading as civilians, now consider it prudent to start going through democratic motions.

Yet North Korea alone remains immune to outside influence and impenetrable by foreign intelligence. We know, having learnt about it 48 hours later, that Kim Jong-il is dead, but nobody has a clue what to expect next. How does this impoverished, artificial state manage to remain such a tight ship?

One reason is that the sort of anxiety attacks provoked in other authoritarian states by dramatic events abroad are a permanent way of life north of the DMZ. North Koreans are inculcated from early childhood with the belief that the whole world is against them and that the nation must remain constantly on guard against foreign intrigue. Even China, the state's most dependable financial and diplomatic prop, is regarded with perennial suspicion.

This posture reflects Korea's long centuries of isolation during the Joseon Dynasty, which lasted almost until its annexation by Japan in 1910: for much of the 19th century it was the mysterious "hermit kingdom". Isolation required permanent vigilance: the peninsula had repeatedly suffered land invasions from the continent as well as by sea from Japan.

History also helps to explain why the outside world, even South Koreans who shared all the north's historical experience up until the peninsula's partition after the Second World War, finds it impossible to prise open the country's élite. Marxism provides the state's rhetoric and imagery but the moral underpinnings go all the way back to the Neo-Confucianism imported from China in the 14th and 15th centuries. More than a religion, this was a moral and ethical system that provided a steel frame for the state's development, founded on such values as chung (loyalty), hyo (filial piety) in (benevolence) and sin (trust). Although the formal apparatus of Confucianism was retired when Korea was shunted into the modern age by Japan, its colonial master, the mental and moral structure is still intact.

Filial piety helps explain the degree of mass devotion to Kim Jong-il and that he was into his 50s before he assumed power: North Koreans would have been uncomfortable with anyone significantly younger taking over from the "Great Leader". This also explains why even the experts hesitate to pronounce on the state's immediate future. Kim Jong-un's exact age is unknown but his cupid lips and chubby cheeks are not those of a father figure. That's why a lot of attention is being paid to his uncle Jang Song Taek, 65, a close adviser to Kim Jong-il and a shrewd survivor; some are casting him in the role of Pyongyang's Deng Xiaoping.