(DURHAM) -- North Korea continues mourning the death of longtime leader Kim Jong Il, who died of a heart attack Saturday at the age of 69. The new leader of North Korean is Kim's son, Kim Jong Un, who takes over at the age of 27. Duke University Political Science Professor Peter Feaver says Kim Jong Un's youth may prove to be a detriment.

"There's a strong preference for older rulers and so there's doubt about the political stability of the regime and in that setting, with a very large military, there's great danger for the world," said Feaver.

Just last September, Kim Jong Un was appointed to some high-ranking posts, setting the stage for him to succeed his father.