A hundred years ago, the victims of such a catastrophe were on their own, but there are now well-established routines for getting help in quickly from outside. We saw them at work in the same region during the tsunami that killed at least twice as many people in 2004. Nothing could be done for those who died in the first fury of the event, but relatively few died from disease, injuries, exposure or sheer hunger or thirst in the days and weeks that followed.

Indonesia, Thailand, Sri Lanka and India — the nations worst hit by the 2004 tsunami — are reasonably well-run countries that were able to help their own citizens, and they had no hesitation in welcoming international aid as well. Burma (which got off lightly in 2004) is very different. The question is: why?

What sane government would block the entry of foreigners bringing exactly the kind of help that is needed — people whose professional lives are devoted to disaster relief — when at least a tenth of the country’s people are living in the open, with little access to food or clean water?

The short answer is that the generals who rule Burma are ill-educated, superstitious, fearful men whose first priority is protecting their power and their privileges.

They almost lost both during the popular demonstrations led by Buddhist monks last year, and they are terrified that letting large numbers of foreigners in now might somehow destabilize the situation again. They are sitting atop a volcano, and they know it.

But that is not really a complete answer, for it begs the question: Why has Burma fallen into the hands of people like that not just for a few years, but for 4 1/2 decades? Thailand has the occasional short-lived military coup, Indonesia had its problems with Sukarno and Suharto, and Cambodia had the horrors of Year Zero, but no other country in the region has been misgoverned so badly for so long.

It seems incredible now, when neighboring Thailand has four times Burma’s per capita income, that at independence in 1948 Burma was the richest country in Southeast Asia. With huge resources, a high literacy rate, and good infrastructure by the standards of the time (due to the British Empire’s obsession with railways and irrigation projects), it seemed fated to succeed. Instead it has drifted steadily downward, and is now the poorest country in the region.

The problem is the army, obviously, but why is the army such a problem? Perhaps it is the legacy of the “Thirty Comrades.” Rarely has such a small group of people dominated a whole country’s history for so long.

The Thirty Comrades were a group of young Burmese students (average age 24) who went abroad in early 1941 to seek military training so they could come home and launch a rebellion against British rule. Most of them were more or less Communist in orientation, and their original intention was to get training from the Chinese Communists.

By chance they fell in with the Japanese instead. They returned under the wing of the Japanese invaders at the end of the year as the “Burma Independence Army,” but switched sides in 1944 when it became clear that the Japanese would lose the war. They combined the authoritarian traditions of the Imperial Japanese Army with the ruthless ideological certainty of militant Marxism, and they dominated the army of the new republic from its independence in 1948.

It was this army, the nastiest behavioral stew imaginable, that seized power in 1962 and has ruled Burma ever since. The last of the Thirty Comrades, Ne Win, only retired in 1988, and continued to exercise great influence from behind the scenes until only 10 years ago.

Whatever ideology the army once had is long gone. It has become so corrupt that Burma ties with Somalia for last place on Transparency International’s corruption index. The country exists merely to serve its armed forces, which have never shown any hesitation in shooting citizens who question their right to rule.

Its commanders are fully aware that most Burmese hate their rulers, and fear that the presence of a large number of foreigners might serve as a spark for another popular uprising. Even if another million and a half lives depend on the rapid delivery of emergency aid to the desperate survivors in the delta, as Oxfam fears, the army will severely restrict the entry of foreign aid personnel as long as it can resist the international pressure to let them in.