Here is yet another report issued on regime collapse in North Korea, this time from the Council on Foreign Relations:

Nearly half a million troops drawn from South Korean, U.S. and other allied forces might be needed to cope with a collapse of North Korea if its military was to respond by mounting an insurgency against foreign forces, according to a report issued by the private Council on Foreign Relations.

Countering such an insurgency would likely take a force of 460,000 troops — more than three times the number of U.S. troops in Iraq, said the report, “Preparing for Sudden Change in North Korea.” The Council, founded in 1921, is a New York-based private think tank.  (……)

To help secure and stabilize North Korea in the wake of collapse, the report says between 115,000 and 230,000 troops would be needed, and possibly tens of thousands of police. But if former elements of the North’s vast military were to wage an insurgency against foreign forces, the size of the force needed to counter them would “escalate dramatically,” according to the report.  [Stars & Stripes]

I have long advocated that US soldiers should be sent into North Korea if the regime collapsed in only the most limited of circumstances, preferably none at all.  The ROK Army should overwhelmingly fill the country with soldiers to exert authority over the north before the Chinese or Russians can move in.

As Robert Koehler correctly points out it just so happens that South Korea has plenty of troops to handle regime collapse if it was in fact to happen:

As of 2006, South Korea had a standing active force of 687,000 (.pdf) with a regular reserve force of 4,500,000. 560,000 of those regulars were in the ROK Army. This means South Korea could deploy 460,000 regulars to North Korea and still have plenty left over to defend Dokdo from the Japanese. This would also mean, of course, that the US would be required to contribute almost nothing to the effort beyond that which is expected of a close military ally — which in the South Korean case, means perhaps an engineering unit, a field hospital and maybe a token “peace and reconstruction” unit to build toilets and restore East German Bauhaus architecture in Hamhung.  [Marmot's Hole]

If the US moves into North Korea that would give the Chinese the green light to move in as well.  That is why it is critical that South Korea quickly deploys it’s forces throughout North Korea and implement martial law and immediately begin humanitarian assistance to exert a sense of authority.  North Koreans have been brought up since the day they were born to hate the United States and if the ROK Army is seen working side by side with the United States in North Korea this may give many North Koreans the impression that the South Koreans are the puppets of the United States.

It is critical that the South Koreans have to be viewed early on as the legitimate occupiers of North Korea by the North Korean population.  Everything done in the early days of a collapse has to be viewed in the context of building the legitimacy of the South Korean government in the eyes of the North Korean population.

Here is what the report recommends that US forces do in North Korea if the regime collapsed:

The report said the U.S. role would “almost certainly not include” having a significant number of ground troops remain in the North, but would instead be to give logistical and other support.

But U.S. forces could be expected to play a key role in finding and seizing weapons of mass destruction and related materials “before any leakage occurs beyond [North Korea’s] borders,” the report said. The stockpiles include an “estimated six to eight nuclear weapons” as well as chemical and biological weapons and ballistic missiles, the report said.

“Although American forces would not likely become directly involved in daily security operations, they could provide vital assistance in the form of transportation services, command, control, communications and intelligence infrastructure, the distribution of humanitarian supplies, and the repatriation of refugees,” the report said.

I don’t see any reason why the ROK Army cannot do all of these missions?  The US military could be best used by providing intelligence and logistical aid for the ROK military in South Korea to deal with the security and humanitarian crisis that is sure to happen if North Korea collapsed.   Also the US Navy should be used blockade the country to ensure no weapons or WMD are being smuggled out of the country.

US forces moving into North Korea would only legitimize any Chinese action into North Korea plus cause a host of issues that can be avoided with a ROK military led occupation of a collapsed North Korea.