Nuclear, missile tests dampen prospects of NK`s collapse . FEBRUARY 21, 2013 09:13. . In 2008, the health problems of the late North Korean leader Kim Jong Il and the designation of his third son Jong Un as his successor increased instability in North Korea, leading to active discussion in the U.S. over a contingency situation in the communist state. Some went as far as to propose large-scale U.S. military intervention in North Korea if the impoverished country collapsed.

Bruce Bennett, a senior defense analyst at the U.S.-based think tank Rand Corp., said in an article published in the fall 2011 edition of the journal International Security that some 260,000 to 400,000 troops would be needed to stabilize North Korea even under the most benign scenario of an implosion. Titled "The Collapse of North Korea: Military Missions and Requirements," he said the troop figure would be bigger than those sent to Afghanistan (94,000) and Iraq (92,000) through 2010.

Bennett said the U.S. would need five operations if the North collapsed: stabilization, border control, removal of weapons of mass destruction, control of conventional weapons and insurgency deterrence.

Theories about North Korea`s collapse have surfaced whenever signs of instability in its power elite appear even after Kim Jong Un became the country`s supreme leader after his father`s death in December 2011.

In July last year, Bruce Klingner, a senior analyst at the Heritage Foundation in Washington, urged the U.S. to prepare a thorough military response posture with allies such as South Korea and Japan. He raised the possibility of a rift within the innermost circle of the North Korean military after high-ranking general Ri Yong Ho was purged.

Pyongyang`s long-range rocket launch in December last year and its third nuclear test on Feb. 12, however, have dampened expectations of a regime change or collapse in the North.

In a recent interview with The Dong-A Ilbo, Stephen Bosworth, former U.S. special envoy on North Korea, suggested that a regime change would be impossible. Whether because of international factors or external pressure, he said, the North is unlikely to see a regime change in a short period of time and China will stop that from happening.

In a symposium on security of the Korean Peninsula on Friday, when asked about the U.S. position on a contingency situation in North Korea hosted by the Institute for Corean-American Studies, Patrick Cronin, senior director of the Asia-Pacific Security Program at the Center for a New American Security, simply said Washington was implementing a policy of inducing change from the bottom through free circulation of information in the North.

Similarly, academic discussions on the possibility of a contingency situation in the North have almost stopped as the North under Kim Jong Un has fared better than expected.

Shunji Hiraiwa, a professor of modern Korean affairs at Kwansei Gakuin University in Japan, said, "North Korea`s third nuclear test indicates that the Kim Jong Un regime is stable enough to conduct it."