The Council on Foreign Relations said that although North Korea defied predictions in the 1990s that it would collapse after the death of its founder, economic meltdown and a deadly famine, the state remains weak and vulnerable.
Change scenarios range from an orderly transfer of power from leader Kim Jong-il to a successor to a possibly violent struggle for power between military factions to a breakdown in political authority that would sow chaos in a country believed to have nuclear, chemical and biological weapons and with millions of armed troops, it said.
"The stakes are simply too high and the risks too great for U.S. policymakers to assume that this will not happen any time soon. ... Kim Jong-il's condition may actually be much worse than press reports suggest and that his capacity to govern -- if it hasn't already been seriously compromised -- may be short lived," said the report.
China and South Korea could end up competing for influence in a post-Kim North Korea, while a humanitarian crisis that spilled refugees over their borders would increase pressure on Beijing and Seoul to intervene, said the report.