No one will even guess when this might happen - within a year, more likely within five years, and almost surely within 10 years? Will the collapse be a "soft landing" in which Mr. Kim's regime gradually falls apart with the pieces picked up by the South Koreans, or will it be a "hard landing" in which Mr. Kim's regime implodes and chaos sweeps the land?

The consequences of a regime change in Pyongyang could be staggering. Immediately, U.S., South Korean and Chinese troops could charge into North Korea to secure its nuclear facilities - and confront each other. Midterm, reviving North Korea could cost South Korea, Japan, China and the United States enormous sums. Long term, a reunited Korea would change the power balance of East Asia - but unpredictably.

Analysts everywhere point to a decade of hunger that has left 7-year-old North Korean children 8 inches shorter and 20 pounds lighter than their South Korean cousins. North Korean soldiers in a regime that gives priority to the military forces have been reduced to two skimpy meals a day. Factory workers nap on the floor for lack of food and energy.

That has led to conjecture that North Koreans, despite the pervasive controls in the Hermit Kingdom's police state, may throw caution to the winds. "We just don't think they can go along with this much longer," said an American official with access to intelligence assessments.

The Peterson Institute for International Economics in Washington reports that North Korea, after 10 years of food shortages, stands on the precipice of famine that could have political consequences. "The possibility of widespread social distress and even political instability," the institute said in a study, "cannot be ruled out."

Another study, from the nonpartisan Congressional Research Service, says: "Dismal economic conditions also foster forces of discontent that potentially could turn against the Kim regime - especially if knowledge of the luxurious lifestyle of Communist Party leaders becomes better known or as poor economic performance hurts even the elite."

Even so, an assessment from Jane's, publisher of security reports, said five years ago: "The only significant power base that might challenge the regime is the military. Since Kim Jong-il became chairman of the National Defense Commission, however, he has promoted 230 generals. Most of the army's 1,200-strong general officer corps owes their allegiance to him." Nothing appears to have changed that judgment - except starvation.

Added to the pressures on the regime is the increasing isolation of Pyongyang. The six-party talks among North Korea, South Korea, China, Japan, Russia and the United States, which are intended to persuade Mr. Kim to give up his nuclear ambitions, are stalled with no end in sight.

China and Russia no longer seem to have an ideological commitment to their fellow communists in North Korea and were clearly miffed when North Korea detonated a nuclear device in 2006. Japan has begun to negotiate warily with North Korea to get an accounting of the Japanese it kidnapped over a long period. Most sanctions remain in place.

Seoul's contacts with North Korea slowed after, among other things, a North Korean soldier killed a South Korean woman taking an early morning walk on a beach near the North Korean resort she was visiting. Moreover, South Korean young people have shown less interest in reconciliation with North Korea than their parents and grandparents because of the cost.

For the United States, officials of the Bush administration are going through the motions of negotiating with the North Koreans for an enforceable agreement under which Kim Jong-il would give up his nuclear weapons. In return, he would get a peace agreement replacing the truce that ended the Korean War of 1950-53, diplomatic relations with the United States, and aid and trade benefits. But little real progress is in sight.

The opening ceremony of the Beijing Olympic Games, a political event if ever there was one, reflected power relations in East Asia. President Hu Jintao of China was the host, of course. U.S. President George Bush, the 43rd U.S. president, was there along with his father, President George H.W. Bush, the 41st. Premier Vladimir Putin represented Russia, Prime Minister Yasuo Fukuda represented Japan, and President Lee Myung Bak represented South Korea.

Kim Jong-il wasn't there.