Editor’s Note: On November 14, 2013, Richard Bush gave a presentation at “Preparing for Collapse in North Korea: Challenges and Issues,” an event hosted by the Center for Security Studies at Angelo State University.

Imagine what East Asia looks like in the view of China’s leaders looking east. There is a chain of islands, all of whose governments have security ties with the United States: Japan, Taiwan, and the Philippines. Then there is the southern half of the Korean peninsula, whose government, the Republic of Korea, has a defense treaty with Washington. The only state on China’s periphery that does not have close and friendly relations with the United States is North Korea.

You can understand from this thought experiment why China’s national security elite might believe that it is in their interests to have a North Korea that is under China’s influence, because it serves as a buffer that provides some strategic depth, just as the Atlantic and Pacific Oceans provide strategic depth for the United States. You therefore get some idea why Chinese leaders are comfortable enough with the status quo, and, in contrast, why they would get very anxious if for any reason the Korean peninsula were to be united under the aegis of the Republic of Korea, particularly because the ROK is allied to the United States. Strategically, therefore, the collapse of North Korea would be a big setback for China.

Of course, in a world where China has no fear of American intentions, it might be willing to see its strategic buffer go away, but that is not the world we live in. China does fear American intentions. Chinese officials do understand that unification may happen someday, whether they want that or not and regardless of what they might do to stop it. But if unification is to happen, Beijing wants it to occur peacefully and result in a new, united Korea that is friendly to China and not closely aligned to the United States. Clearly, Chinese leaders prefer the status quo to instability or radical change in North Korea, and when Beijing has feared that instability is growing, it has sought to use its economic, political, and diplomatic influence to reverse that trend. It did that as recently as three years ago.

But what would Chinese leaders do if they saw signs that North Korea was falling apart and putting at risk their strategic depth?

My most honest answer to that question is, “I don’t know.” What China would do certainly depends on the circumstances, which are not easy to define in advance. There would be many factors at play. Moreover, China’s decision-making structure is pretty opaque, but no country’s leaders will advertise their likely actions in advance. Honestly, I suspect that Chinese leaders themselves haven’t made up their minds as to their response to a looming North Korean collapse. So it’s a bit difficult for me as an outsider to know. All that any specialist can really do when considering the topic he gave me is to engage in informed speculation. Such speculation is particularly important on situations that are low probability and high impact. In the case of a North Korean collapse, the consequences are very high impact and might include war between the United States and China, the first war between two countries with nuclear weapons.

So why might Chinese leaders decide that they should intervene if the North Korean status quo started dissolving?

The first is a fear that a large number of North Korean citizens, seeking to escape a humanitarian disaster and physical danger would begin coming across the border into China. Indeed, the flow began during the famine of the 1990s and has continued at rather low levels until this day. What I’m talking about and what Chinese leaders would fear is an outcome that is orders of magnitude larger. Some observers have predicted that under certain circumstances we could be talking about several million people. Even 10 percent or one percent of that would destabilize Northeast China and place a serious strain on the authorities.

The second reason I have already mentioned. That is, China would wish to preserve the buffer that North Korea has been for China. It would fear that if it did not act first, South Korea and the United States would do so and create a democratic and united Republic of Korea allied with the United States on China’s border. This would be not only a strategic disaster but also, over time, a political challenge to China’s own authoritarian system. The only way for China to prevent such an outcome would be for it to act first.

One reason that Chinese leaders would worry about South Korea acting first is because they know that many South Koreans fear that China would move quickly to seize a collapsing North Korea and make it a Chinese province. This would be a nightmare scenario for South Koreans because it would deny them the long-cherished dream of Korean unification. Indeed, actions by China contributed to this fear. I actually think the fear is misplaced, but it is real in South Korea.

Third, in an unstable North Korea, China would fear that some faction might be tempted to use weapons of mass destruction against China. The fact that those weapons are probably in the northern part of North Korea makes it easier for China to seize them. For example, the nuclear complex at Yongbyon is 130 kilometers from the Chinese border. It’s not the only nuclear site but it’s the major one.

In addition to these specific reasons, there are also some general statements about the calculus of Chinese leaders that would incline them to intervene.

First of all, they do not like uncertainty, and they especially don’t like the extreme uncertainty that the collapse of the North Korean state would entail.

Second, Chinese leaders are not very good at assessing situations that they haven’t experienced before. This is not just a Chinese trait, of course, but their institutions for analyzing what is going on in other countries and what the leaders of those countries intend to do is not always objective. Chinese analysts tend to tell their own leaders what they think the leaders want to hear.

Third, Chinese leaders don’t like to take external risks when they conclude that they don’t have to. When they are comfortable with the status quo, they would like to preserve it. Again, this is not a trait unique to China, but Chinese leaders are quite conscious of China’s weakness, especially compared to the United States, and very aware of the dangers of domestic instability.

Fourth, on the other hand, they have a pretty clear sense of China’s interests. Indeed, they have defined their “core interests” to be China’s sovereignty and territorial integrity; its economic prosperity; the survival of the communist state. I would bet that they would see all three of these interests under threat if North Korea began collapsing before their eyes.

Fifth, Chinese leaders, like their counterparts in other countries, have the greatest difficulty in picking a course of action in a crisis – when the situation is very confused, when core interests are at stake, when time is short, and when the danger of war is real. They are liable to misread the intentions of their adversaries, and they have a natural temptation to preempt before they lose initiative and are placed at an extreme disadvantage.

If we combine these general characteristics with the specific reasons I mentioned earlier, I am led to the inference – and it is only an inference – that Chinese leaders not sit idly by if they saw North Korea collapsing. And they would be very unlikely to sit idly by if they feared that their strong adversaries – the United States and South Korea – were not self-restrained. Under those dire circumstances, Chinese leaders would be more likely to act to protect China’s interests than to not act. It would preemptively intervene because it would worry that Washington and Seoul will beat China to the punch.

This is the first part of my informed speculation. It’s just an inference from what we know about Chinese assessments on North Korea and what we know about how well Chinese leaders respond to challenges to their country’s interests. But it’s only general speculation. I need now to go into more depth, in two respects. The first is to explore the varieties of this concept of collapse. The second is to look a bit at Chinese capabilities to intervene.

When we consider the word “collapse,” at least three different types of radical change come to mind:

• What I would call a Type One collapse would be essentially a coup in which elements of the North Korean system act to end of the Kim Family Regime, which has ruled the country since the 1950s. The leaders of the coup would quickly establish their position, without destabilizing the system’s control. The result would be a communist dictatorship without a monarch at the top, but sustaining many of the policies we have seen.

• A Type Two collapse might start as a coup, but the leaders of the coup would not quickly establish their control and a new regime. Instead, the coup leaders and their opponents would line up on two sides. All parts of the regime would have to align with one of the two coalitions. The result would be bitter and violent civil war. The crisis would be prolonged and lead to disorder, destruction, and a serious humanitarian emergency. One side would ultimately prevail and establish its dictatorship. The North Korean state would survive but it would be severely weakened.

• A Type Three Collapse is where internal conflict is so severe and prolonged that the North Korean state itself disappears. Some kind of unification would follow.

Obviously, each of these types of collapse poses a different degree of difficulty for China. At one end, a coup that quickly created a new communist dictatorship but without the Kim family at the top is easier to cope with than a civil war or the end of the North Korean state. At the other end, Chinese leaders would be inclined to see the end of the North Korean state as a strategic disaster. A civil war would be in the middle, but would still be very difficult to cope with. And China’s intervention would probably vary with the type of collapse we are talking about.

For a Type One Collapse – a successful coup that ends the Kim family regime, I expect that China would need only to intervene politically. It would seek to quickly align with the new North Korean leadership and to attempt to secure even deeper influence than China has had with the Kim Family. One reason for doing so would be prevent this Type one Collapse from evolving into Type II or Type III. But because China has better access to the current North Korean regime than any other country, and because it already has a significant presence in the economy, it is liable to be fairly successful. Of course, China would be alert to the beginning of refugee flows into China, but they might not even happen. Beijing has always somewhat embarrassed about the communist monarchy on its border, and this type of collapse would remove that.

In a Type Two Collapse – a civil war – Chinese leaders would worry first about a humanitarian emergency that spills across the North Korean border into Northeast China. Outside observers tend to believe that Beijing would tighten its control over the border and even move military and other units across the border to establish a zone in which refugees could be held and cared for as long as necessary. One expert believes that because the terrain at the border is fairly rugged, Chinese units would have to move in between 50 to 100 kilometers to establish effective control.

In addition, Chinese leaders would probably have to face requests from each of the contending sides to support its cause politically, to provide it with material assistance, and, as necessary, to make Chinese territory available for sanctuary. I would speculate that China would be as reluctant to get drawn into the conflict as President Obama has been to intervene in the Syrian civil war – until it became clear which side was going to win. Then it would likely move to line up with the winner, provide certain types of support, and then maximize its influence over the successor regime.

In a Type Three Collapse – the end of the North Korean state after an extended period of internal conflict – China would be in a serious dilemma. On the one hand, it won’t wish to get entangled in the civil war that would precede collapse. On the other hand, Chinese leaders would worry that the South Korea and United States would intervene to protect their interests, and so be sorely tempted to intervene preemptively.

Chinese leaders want as little change as possible. If collapse began, they would want to limit the degree in the hope that it would not go so far. That is, if there were a coup, Beijing would fear that it might deteriorate into civil war, and so try to stop that deterioration. Yet as much as China might like to control the situation on the Peninsula, directly or indirectly, it may find that difficult to do.

The second complicating factor is China’s capabilities to intervene in different ways. China’s interests dictate that it try to preserve primacy of influence in Pyongyang as well as preventing a spill-over of chaos into China. That suggests some kind of intervention. On the other hand, would China be able to carry out the sort of intervention that its leaders believed the circumstances required? Chinese leaders might be reluctant to intervene in contingencies where the capabilities they possess are insufficient to the mission.

I have already indicated that Chinese capabilities to intervene politically after a coup are probably pretty good. And we have some feel for the missions the People’s Liberation Army has prepared for. They include:

• Humanitarian missions such as assisting refugees

• Peacekeeping or order-keeping

• Mitigating the effects of an environmental disaster following the misuse of weapons of mass destruction.

These missions are important but they are pretty modest when compared to a full-scale intervention in hostile circumstances.

When it comes to stopping refugees from entering China but providing them with assistance at or near the border, I have heard that China is preparing for around 300,000 people. It appears to have handled the challenge several months ago of around 50,000 people from Burma who were trying to cross into China. So 300,000 is not out of the question, but the border with North Korea is long and the terrain rugged in many areas. But if many more North Koreans tried to come across, it might overwhelm Chinese preparations.

Where capabilities are more in question is the mission of a ground intervention deep into North Korean territory, including a race for Pyongyang against South Korean and American forces. China certainly has ample ground forces for such an operation, including those deployed in China’s northeast, which is closest to North Korea. Reinforcing those units would not be difficult, since the PLA has practiced moving troops around the country. The geography of North Korea’s western coastal area is low-lying and fairly flat. So it would be a pretty easy march to Pyongyang if – and this is an important if – there is no opposition. If North Korea’s collapse was total and there was no indigenous resistance to the Chinese intervention, it might actually be easier for the Chinese ground forces to get to Pyongyang. The problem in this situation would be that the Korean and American navies and air forces would be likely to prevail in a struggle for control of the waters of what Koreans call the West Sea and Chinese call the Yellow Sea, and of the skies above those waters.

But the challenge facing Chinese forces becomes even more serious if a North Korean faction or factions decide to oppose or complicate a Chinese intervention. China’s military has not fought a major conflict or engaged in major combat operations since 1979, when it went into Vietnam. And that was far from a roaring success. Preparing for such an intervention would entail substantial training and exercises at a minimum.

If there were a race between China and the U.S.-ROK alliance to take over North Korea, clashes between those two sides would be inevitable. Full-scale combat would not be impossible. Neither the United States, South Korea, nor China would seek a war, but they might decide that staying out of North Korea would be such a political defeat that they would intervene anyway. The ultimate danger, of course, is that the conflict escalates beyond conventional forces to nuclear weapons. Let me assure you that such an outcome is highly unlikely, but once major conflict begins the probabilities start to rise.

Which is why the United States and South Korea and China have an interest in reducing the possibility of conflict to as low a level as possible. And the best way to do that is to talk in advance in secret to work out understandings about the impact of a North Korean collapse on the interests of the three countries and how to avoid the worst. For example, clashes and conflict would be less likely if Beijing, Washington and Seoul could work out a division of labor regarding whose armed forces do what in various kinds of collapse and a provisional division of territory. At the political level, perhaps the United States and South Korea could provide credible assurances to China that in a unified Korea under South Korea’s control, U.S. forces would stay below the 38th parallel and not get close to China.

Actually, the United States and South Korea have each sought such a conversation with China (we talk to each other all the time). President Obama has raised the pressing need for the discussion of collapse contingencies with China’s new president when they met in California in June. But China has been extremely reluctant to talk with us. The most obvious reason is that Beijing would get into a lot of trouble if North Korea found out that China was talking to the United States about it behind its back. And China has good reason to question the ability of the United States to keep anything secret. The other reason is that China is very suspicious about American intentions, whether our officials say to their Chinese counterparts. The mistrust is probably deepest within the Chinese military.

To sum up, the current Korean status quo is not too bad from China’s point of view. A collapse of North Korea would present China with one of the most serious external challenges it has ever faced – strategically, politically, and operationally. The more extreme the collapse, the more difficulties China’s leaders and its armed forces would face. At a minimum, there would be a humanitarian crisis. Much more serious would be the prospect of a South Korean and American intervention. In responding, there are some things China could probably execute pretty well today, such as creating a narrow zone at the border to hold and care for refugees. More ambitious missions would be harder, but Chinese leaders might decide that they have no choice but to intervene in force. The risks of doing so are so high for China, South Korea, and the United States that there is every reason for the three governments to work to avoid the worst.