Much of the commentary about North Korea after the death of Kim Jong Il has sidestepped the question of reunification. While the nations of Germany and Vietnam were united, Korea remains split into two. In this part of the world, the Cold War is not over, and there is a real danger that it might turn into a hot war.

North Korea is committed to unifying the nation by military means. Its pursuit of nuclear weapons is not solely for defensive purposes. South Korea does not have its own nuclear weapons, and thus a U.S. withdrawal would leave them vulnerable to a nuclear-armed North.

Various scenarios could play out if the leadership transition goes sour. The worst case would be chaos and civil war, possibly leading to Chinese intervention.

Unification with South Korea seems extremely unlikely. South Korean President Myung-bak Lee cut all contacts after last year's military attacks by Pyongyang, and no fresh initiatives from Seoul can be expected until parliamentary and presidential elections next year.

Sixty years after the armistice, a new generation of Koreans has grown up for whom the Korean War is something their grandparents lived through. They now enjoy life in a prosperous democracy and seem reluctant to shoulder the burdens that unification would entail — from the risk of war to the economic costs of reconstructing North Korea.

Unification aside, nationalism plays a leading role in South Korean politics. The legacy of World War II and the Cold War is embedded in a tense triangular relationship between China, Japan and the Koreas, where historical enmities play out in clashes over territorial claims over the surrounding waters.

On Dec. 14, hundreds rallied in front of the Japanese Embassy in Seoul to demand reparations for the estimated 200,000 Korean women forced into sex slavery during World War II. Two days earlier, a Chinese fisherman stabbed to death a Korean naval officer who had boarded his Chinese vessel, which was fishing in Korean territorial waters. And leftist protesters continue to mass in the streets of Seoul in opposition to the new free-trade agreement with the United States that was ratified by the South Korean parliament last month.

It will take the combined efforts and goodwill of China, Russia, Japan and the United States to ensure that the situation on the peninsula does not spiral out of control.