The weird and scary saga of how an isolated, bankrupt nation went nuclear—and how the United States failed to stop it

Great historical events can spring from small slights. Kaiser Wilhelm never forgave the French for not treating him to a parade in Paris. "The monarchs of Europe have paid no attention to what I have to say," the German emperor whined before setting the Continent aflame in 1914. By many accounts, North Korea's Kim Jong Il also suffers from a tender ego. For one thing the 5-foot-3 dictator is sensitive about his height (hence, one suspects, his bouffant hairstyle and elevator shoes). After ordering the kidnapping of a South Korean actress, Choe Eun Hee, in 1978 to help him start up a national film industry, the first thing the movie-mad Kim jokingly asked her at a welcoming dinner was: "Well, Madame, what do you think of my physique?" More painfully, he fears that in the eyes of his countrymen and allies, he can never match the achievements of his revered father, the "Great Leader" Kim Il Sung (who was close to six feet tall and who led a guerrilla army against the Japanese occupiers in the 1930s). By many accounts, the young Kim is fed up along with his top aides, who often reflect his views. "What I hear is, Big Brother is telling Little Brother, 'Don't do that'," the North Korean vice minister of Foreign Affairs, Kim Gye Gwan, complained when Beijing urged Kim Jong Il to cancel his planned missile tests in July. "But we are not boys. We are a nuclear power."...

... Last week's half-kiloton explosion was the product of an effort spanning a half century or more. It is difficult to pinpoint the precise moment Kim Il Sung decided he needed the Bomb and a ballistic-missile program to go with it. But the ambition was in keeping with his deep insecurity going back to the dubious origins of his regime.

North Korea, after all, is an invented country, a relic of the cold-war divide. After the World War II defeat of Japan, which had occupied Korea, the regime was created by Stalin in 1945 out of the northern half of the Korean Peninsula, and Moscow propped up Kim Il Sung as a strongman. The Americans, meanwhile, built their client state in the southern half. Both sides never gave up their claims to the whole peninsula, putting them on a permanent war footing. To consolidate power, Kim created a cultlike ideology of self-reliance called juche, a curdled brew of traditional Korean xenophobia and nationalism, Confucian deference to authority and utopian Marxism-Leninism. Some experts argue that Kim decided he needed a nuclear security blanket soon after the 1950-53 Korean War, which he battled to a draw. Then came the early 1970s, when he realized he was losing the economic contest against his blood enemies in Seoul, and after that the Soviet Union disintegrated—a failure that suddenly left Pyongyang without a communist patron or a nuclear umbrella to shield it. An increasingly paranoid Kim Il Sung also sponsored many acts of terrorism against the South, including the alleged sabotaging of a Korean Airlines plane in 1987, killing all 115 passengers and crew, the year before the Seoul Olympic Games. And he taught his son well.

Driven by two men with near-absolute power, North Korea's program was produced by a staggering cast of characters. They included idealistic Korean scientists educated in Imperial Japan and repatriated after World War II, their students educated in the Soviet Union and the thousands of homegrown technicians. Japan, one of the North's hardiest enemies today, gave Pyongyang the man deemed the"first father" of North Korea's nuclear program, the late scientist and inventor Lee Sung Ki, who earned a degree in chemical engineering at Kyoto Imperial University in 1931. In fact, despite its deep isolation, the Hermit Kingdom is known or suspected to have received nuclear assistance from 14 countries: Russia, China, Austria, France, Canada, Romania, Germany, Pakistan, India, Japan, Iran, Ukraine, Kazakhstan and the Democratic Republic of Congo.

There were privateers, too: defectors, Chinese technology firms, Japanese trading houses and front companies scattered from Thailand to Scandinavia—all provided critical technologies, components or know-how by circumventing a global nonproliferation regime designed to thwart such commerce. Even the International Atomic Energy Agency unwittingly helped: analysts say a single North Korean diplomat, Choi Hak Gun, who was posted to IAEA headquarters in Vienna from 1974 to 1978, scoured the agency's library for nuclear know-how.

The human costs of North Korea's nuclear ambitions on the nation's best and brightest were terrible. Few paid a higher price than Kimchaek University's class of '62, according to a grad who defected from North Korea several years ago and told NEWSWEEK his story. As graduation at the elite college neared more than 40 years ago, the buzz on campus was that Kim Il Sung had ordered construction of an advanced research facility to study atomic energy, and that patriotic young scientists soon would be mobilized to work there."Our professors really pushed the need for nuclear development," he recalls."The rumor circulating among students was that those of us sent there wouldn't have long to live."

The defector, spared the fate of those assigned to nuclear labs, spent his adult life watching unlucky classmates grow sick, weak and despondent. On leave, one confided a Confucian desperation to marry and sire children before radiation rendered him sterile."It was exactly what we feared," the defector says, still saddened by their sacrifice."These guys went bald. Many of them lost their eyebrows. Some of them had constant nosebleeds. They looked so weak it was hard to even face them. The thinking was, 'If one scientist falls there will always be others to take his place'." That logic not only ravaged a generation of scientists sent like worker bees into toxic nuclear labs. It cost billions in hard currency that might have fed starving people and hobbled the national economy by imposing perpetual austerity under slogans like"Military first."