Yesterday, Kim Jong-un sent an unmistakable signal that he is serious about negotiating with the United States.  He fired his top three military officials, according to U.S. sources and South Korea's Yonhap News Agency, replacing them with at least one "moderate" and showing the army that he is firmly in control.

Reuters:

Kim's motivation remains unclear but analysts said the shake-up allows him and the ruling party to tighten control over the Korean People's Army (KPA) at a critical time of international engagement and domestic development.

"If Kim Jong Un is set on making peace with the U.S. and South Korea and dealing away at least part of the nuclear program, he will have to put the KPA's influence in a box and keep it there," said Ken Gause, director of the International Affairs Group at CNA, a non-profit research and analysis organization.

"This reshuffle has brought to the fore the officers who can do just that. They are loyal to Kim Jong Un and no one else."

It is believed in intelligence circles that Kim does not enjoy the same kind of absolute obedience of the military given to his father and grandfather.  He has been in power since 2011 and has slowly weeded out officers whose loyalty to him personally was in question.  This bold move to reshape the military leadership may be the culmination of a long process.

Citing an unidentified intelligence official, Yonhap said No Kwang Chol, first vice minister of the Ministry of People's Armed Forces, had replaced Pak Yong Sik as defense chief, while Ri Myong Su was replaced by his deputy, Ri Yong Gil.

North Korean state media previously confirmed that Army General Kim Su Gil had replaced Kim Jong Gak as director of the KPA's General Political Bureau. ...

Given the military's secondary role in the North's nuclear and missile programs, the moves are likely more about installing a younger, even more trusted cohort of officials who Kim Jong Un can rely on as he confronts a variety of domestic and international issues, said Michael Madden, a North Korea expert at Johns Hopkins University's 38 North website.

As the Reuters article points out, this is a significant generational change:

The moves are likely linked in part to Kim Jong Un's drive to have the military take a bigger role in critical infrastructure projects.  That could explain why newly appointed director of the KPA's General Political Bureau, Army General Kim Su Gil, accompanied Kim Jong Un on a field guidance trip to a beach tourist zone with other officials, Madden said.

Kim Jong Un is also likely expecting to receive more international economic aid and investment soon as part of the ongoing talks and he wants to prevent corruption that plagued some past projects, Madden said.

All of the newly promoted officials are younger than their predecessors, including 63-year-old Ri Yong Gil, who is 21 years younger than Ri Myong Su.

"This points to two things: the consolidation of Kim Jong Un's power as the sole leader of North Korea and strengthened cooperation between the North's party and military as the country works towards further economic development," said Yang Moo-jin, professor at the University of North Korean Studies in Seoul.

There should be little doubt now that Kim has accepted the fact that his family's longstanding policy of relying solely on the country's domestic resources – known as juche – is about to be at least partially abandoned in favor of international engagement.  But how much will North Korean society open up?  As Reagan once said, "a bird on a tether, no matter how long the rope, can always be pulled back."  That's why we shouldn't look for Earth-shattering change from the regime. 

But any change will be welcome.