The death of North Korean leader Kim Jong Il on Saturday, reported by Pyongyang's special broadcast from noon Monday, could destabilize the isolated communist country as well as all of the Korean Peninsula. Events unfolding in the North Korean leadership must be watched carefully to prepare for possible deterioration of regional stability.

Mr. Kim, reported to have suffered a stroke in 2008, died of a heart attack on his train due to "great mental and physical strain caused by his uninterrupted field guidance tour." His death may have come too early for his third son and heir apparent Mr. Kim Jong Un, who was appointed general and to high-level positions in the ruling Workers' Party of Korea in September 2010.

North Korean mass media called Mr. Kim Jong Un a "superb leader of our party and military," and he heads the funeral committee. But it is hard to say that his power has been consolidated. Although he is vice chairman of the party's Central Military Commission, he is not a member of the National Defense Commission, the highest leadership body of the North Korean state power. Believed to be 27 or 28 years old, he has not yet proved his capacity as a national leader. To camouflage his weak leadership, he may resort to saber-rattling such as testing nuclear devices, test-launching missiles and carrying out localized military provocations.