Perhaps the world's most reclusive leader, Kim Jong Il appeared older, grayer and thinner as he limped his way into his first public appearance before a large audience in more than six months. 

His arrival onstage dispelled questions about whether Kim has recovered from the stroke he is believed to have suffered last August -- he appeared alert and enjoyed full use of both arms, unlike in some of the undated footage broadcast in recent days by North Korea's state-run television.

Yet the frailty of the 67-year-old dictator renewed talk about North Korea's future, with no clear succession policy in place. 

"That process should begin very soon -- otherwise, the country is in real danger of implosion once he's gone," said Bruce Bechtol, an international relations professor at the Marine Corps Command and Staff College.

On her tour of Asian capitals two months ago, Secretary of State Hillary Clinton stoked regional anxieties when she spoke, in unusually blunt terms, about the possibility of a new regime in Pyongyang. 

"(Asian leaders) are confronting a lot of worries about what's up in North Korea, what the succession could be," Clinton told reporters aboard her plane. "I think our goal is to try to come up with a strategy that is effective in influencing the behavior of the North Koreans at a time when the whole leadership situation is somewhat unclear." 

Clinton later denied her comments were provocative, saying "the open press is filled with such conversations. This is not some kind of a classified matter that is not being discussed in many circles." 

Kim Jong Il inherited supreme power 15 years ago from his father, Kim Il Sung, the communist nation's founding ruler. That has created speculation that one of Kim's own three sons will take over when he is gone. 

But the eldest, 37-year-old Kim Jong Nam, told reporters in Macau this week it won't be him. 

The other two, Kim Jong Chul and Kim Jong Un, both in their 20s, did not run for parliament last month. Their father, by contrast, had assumed important positions in both the Communist Party and the military some 20 years before his ascension to power. 

Bechtol described the unique hold on power Kim Jong Il had developed. 

"In the army, none of the generals have a power base that they could actually control the country. In the party, none of those individuals actually have a power base that they can control the army. So what you need is someone like Kim himself, who actually has a power base both in the party and the army, like his father built for him," Bechtol said. 

Clinton spokesman Gordon Duguid underscored the difficulties in tracking Kim and his inner circle. 

"Who is actually taking decisions is very opaque as well. We don't have any direct contact on the ground and are not able to well judge what we hear coming out of North Korea," he said in February.