Others say Kim was threatened by Jang and banished him to pacify political elites in Pyongyang, adding that Jang's wife played a decisive role in her husband's return to power.
Jang soon repaired his reputation within the party. But the family endured tragedy when the couple's only daughter, Geum Song, committed suicide in Paris in 2006. Analysts say she had wanted to marry a foreigner against her parents' will.
The resilient Jang Song Taek is poised to make his biggest political mark yet on his native North Korea, analysts say. Jang has good relations with all of Kim's three sons and has overseen their educations, experts say. He is believed to back the youngest, 26-year-old Jong Un, as Kim's successor.
"He may think it is the only way to sustain his power," said Cheong Seong-chang, director of the Inter-Korean Relations Studies Program at the Sejong Institute. "If he gives Kim Jong Un a boost as the successor, he would . . . play a role as a guardian."
Despite Jang's slim chances of running the nation, some experts wonder what kind of ruler he would make. "He is a smart man with rationality and reason," said Jang Sung-min. "Who knows, if he took over for Kim, he might take North Korea in a totally different direction."
Ju-min Park of The Times' Seoul Bureau contributed to this report.