By Victor Cha This post originally appeared in the Financial Times as an Op-ed. Re-posted with permission.

Until this weekend, any expert assessment inside or outside the US government would have stated that the most likely scenario for a collapse of the North Korean regime would be the sudden death of the isolated leader Kim Jong-il. After Monday’s revelation by North Korea’s state television, we now face that uncertain scenario.

This is a watershed moment. It is not at all clear that the plan to hand power to Kim’s youngest son, Kim Jong-eun, can be carried out successfully. Kim Jong-il had 14 years to prepare to take over from his father, Kim Il-sung, who died in 1994. Kim Jong-eun has had just three years since his father had a stroke. He is not even 30 years old.

He has had little preparation in cultivating his own followers. He has no new ideology to associate with his rise to power. I could not think of less ideal conditions – in a North Korean context – under which the so-called “Great Successor” could be given the reins of power. The plan was to surround Jong-eun with elders, including Kim Jong-il’s sister, Kim Kyong-hui.

Now, however, there are rumors that Kyong-hui is also unwell. This leaves the young son and his uncle, Chang Sung-taek, Kim Kyong-hu’s husband, which is not exactly the dream team to lead the North out of its morass.

Moreover, there have been rumors that the military has been unhappy with the promotion of the young son in September 2010 to a four-star general because he has never served in the army.

The power transition in 1994 was difficult. This one is arguably even harder, and more likely to fail. So what can Washington do? Basically, watch, wait, and prepare.

The US and South Korea have developed military plans for contingencies involving North Korean instability. The first step would be to raise the alert status for the US and South Korean combined forces that maintain peace on the peninsula.

While no military actions are warranted at the moment, the first sign of instability within the North will immediately raise questions about what it might do with its nuclear weaponry, as well as with its conventional military forces.

China is the only country that has eyes inside North Korea. The US and South Korea have been appealing to China to engage in a dialogue about possible instability in the North since Kim Jong-il suffered a suspected stroke in 2008.

Beijing has been reluctant but now may have little choice in the matter. Chinese statements thus far have predictably urged calm and the preservation of stability. Beijing is already on record expressing support for the leadership transition, but presumably this was on the assumption that Kim junior would take power years from now, not today. Despite Chinese statements of support for North Korea, debates still rage about whether to keep supporting the broken country, and these can only intensify with Kim’s death. Does the next Chinese leadership, under Xi Jinping, truly want to go “all in” and fully adopt North Korea as another poor north-eastern province? It is a big burden that we cannot simply assume China would embrace.

Now, Washington, Seoul and Beijing must co-ordinate and ensure that they are operating from the same information as they try to decipher what comes out of Pyongyang.

The moment is dripping with irony. Just last week, the US was engaging in painstaking diplomacy with the North Koreans on food aid agreements and recovering the remains of prisoners of war, as a prelude to returning to the negotiations on denuclearisation. These bits of diplomacy constituted small bites of the apple. We are now talking about a whole new apple.

Approaching the post-Kim Jong-il leadership is not advisable, in part because we do not know who is really in charge. Contacting the young son could do more to alienate him within his own system of anti-American military generals. Establishing contacts with others involved in politics or the military could emasculate the young leader’s authority and set off unknown and destabilizing dynamics.

We do not know North Korea’s future after Kim Jong-il. But if this decrepit regime were to finally collapse under its own weight, there are a host of factors analysts would be able to point to – including economic decay, food shortages, an unstable leadership transition and an increasingly restless population – which could make the Dear Leader’s death the straw that broke the camel’s back.

Victor Cha is a senior adviser and holds the Korea Chair at the Center for Strategic and International Studies (CSIS.) His book, The Impossible State: North Korea’s Past and Future, will be published in 2012.