The ouster of Jang Song-taek, widely seen as the eminence grise of the North Korean regime, is prompting experts to speculate how Kim Jong-un has managed to consolidate his power much faster than his father Kim Jong-il.
Kim Jong-il started working for the Workers Party in 1964 and prepared his ascent to power for three decades until his father Kim Il-sung’s death in August 1994. But Kim Jong-un was named as the heir apparent in 2007 and became the leader less than four years when his father died in December 2011.
"Early in the young Mr. Kim’s tenure, American intelligence assessments questioned whether he would have the staying power to remain in office, and said he was regarded by the North Korean military as spoiled and naive," the New York Times said Tuesday.
Jang and his wife Kim Kyong-hui, Kim Jong-il's sister, acted as mentor and guardian to Kim Jong-un after his father's death. Kim Jong-un quickly seized and consolidated his power by replacing nearly half of the senior officials in the party, government and military. He also ousted Army chief Ri Yong-ho, the other guardian his father appointed for him, in July last year.
Some pundits say the hereditary system is so established in North Korea by now that it is quite natural that Kim Jong-un did not have to struggle for decades to establish his legitimacy.
http://english.chosun.com/site/data/html_dir/2013/12/05/2013120501852.html