Νorth Korea’s brash pursuit of weapons of mass destruction and disregard for chemical weapons norms are enormously troubling. Yet as the current unproductive exchange between that country and the United States demonstrates, China’s engagement will be essential for ensuring North Korean President Kim Jong Un does not resort to the use of chemical weapons. Such a strategic miscalculation could be the spark that could bring the region to war.
Over the weekend, North Korea followed a parade of new missiles and launchers with another show of power that failed spectacularly—a missile blew up soon after launching. But while the world is nervously trying to gauge North Korea’s nuclear capabilities, chemical weapons are said to be firmly within North Korea’s grasp and could be used against a neighboring country, with devastating consequences for all.
North Korea, which remains outside of the Chemical Weapons Convention, is reported to possess up to 5,000 tons of 25 chemical agents and has been implicated in the recent assassination of the North Korean president’s half-brother, Kim Jong Nam, in Malaysia. The weapon of choice was reportedly the lethal nerve agent VX.
Should Kim decide to employ chemical weapons, the targets would probably be external, likely South Korea or Japan, or perhaps even U.S. forces in the region. In any case, such an attack would place the United States and its close allies in a dangerous predicament.
Nations throughout the region would certainly, and swiftly, call for military action. South Korea would likely see this as the opening salvo in a return to open hostilities. Japan remains sensitive about this issue following the deadly 1995 sarin nerve gas attacks on Tokyo by the cult Aum Shinrikyo. Japanese Prime Minister Shinzo Abe has already expressed concern about North Korea’s possible use of chemical weapons, speculating in front of parliament that North Korea may already have the capability to put chemical warheads on missiles. Both governments would undoubtedly be under great pressure to respond should a chemical attack occur.
Furthermore, the U.S. has maintained a presence in the region for almost 70 years, clearly establishing Japan and South Korea as key allies with vital national interests to be defended. Pressure to defend these key allies would be considerable and immediate.
However, even a reaction that would include limited strikes, such as those against the Syrian airbase, could be taken as the leading edge of operations to bring down the North Korean regime by force. The result could be the shelling of Seoul, a city of over 10 million people, with catastrophic consequences. The counterpunch to such a North Korean action by allied forces would likely be equally swift, resulting in a return to open hostilities on the Korean Peninsula.
To prevent the unthinkable from occurring, the North Koreans must be dissuaded from using chemical weapons. They must be convinced that the use of chemical weapons is a red line that cannot be crossed. China should consider being the messenger for this message.
China also should consider taking an active, forward-looking approach to prevent the use of chemical weapons by North Korea. When Syria deployed chemical weapons, there was speculation that Russia may have been complicit or at least aware of plans to conduct the attack.
There can be no ambiguity about the consequences of the use of chemical weapons. China would need to make clear that the result would be a severing of diplomatic ties between the two nations, closing of the China-North Korea border, an embargo for all trade that is occurring to include humanitarian support, and active global condemnation led by China as a result of chemical weapons use.
Should North Korea fail to be dissuaded from launching a chemical attack, any response should be coordinated with allies in the region and not result from a unilateral decision by the United States as was done in response to Syria. Such a response would do well to include the full authority of the United Nations and be executed by an international coalition.
A strong message needs to be sent that the use of weapons of mass destruction will not be tolerated.
So, What if U.S. invades DPRK
The only thing more alarming than a military confrontation between the U.S. and North Korea (the DPRK) would be a military confrontation between the U.S. and China. Yet as tensions between the United States and the DPRK continue to rise, too few analysts are considering the danger of China intervening militarily in response to a U.S. strike on the DPRK’s nuclear weapons and missile programs. This oversight is surprising, especially given that China is legally obligated to render military assistance to North Korea if the U.S. launches any kind of armed attack.
On July 11, 1961, China and the DPRK signed the Sino-North Korean Treaty of Friendship, Cooperation, and Mutual Assistance (中朝友好合作互助条约). Article 2 of the treaty states:
The Contracting Parties undertake jointly to adopt all measures to prevent aggression against either of the Contracting Parties by any state. In the event of one of the Contracting Parties being subjected to the armed attack by any state or several states jointly and thus being involved in a state of war, the other Contracting Party shall immediately render military and other assistance by all means at its disposal.
Article 2 is not a paragon of clarity. A “state of war” (战争状态时) is not defined by the treaty and, more generally, is not a meaningful term under the laws of war. “Other assistance” and the type of military aid to be provided are also not specified. Nevertheless, the article’s meaning, given its construction in the original Chinese, is quite clear—any armed attack against North Korea requires a military response from Beijing as well as other assistance.
Indeed, Article 2 arguably imposes a greater legal obligation on China to defend the DPRK than the U.S. has undertaken in any of its mutual defense agreements. For instance, Article 3 of the 1954 U.S.-South Korea Mutual Defense Treaty states:
Each Party recognizes that an armed attack in the Pacific area on either of the Parties in territories now under their respective administrative control, or hereafter recognized by one of the Parties as lawfully brought under the administrative control of the other, would be dangerous to its own peace and safety and declares that it would act to meet the common danger in accordance with its constitutional processes.
The U.S.-ROK treaty is thus full of limitations on U.S. obligations to defend South Korea that do not exist in the China-DPRK treaty: 1) it applies only in the Pacific; 2) it applies only to attacks on the Parties in “territories under administrative control”; 3) it requires only “act[ing]… in accordance with  constitutional processes.” There is no specific requirement that the U.S. even provide military assistance to South Korea, much less the “immediate… military assistance… by all means at its disposal” that China has promised the DPRK.
We do not claim that the mere existence of a treaty obligation will force China’s military involvement in the DPRK against its will. But the treaty is not a meaningless Cold War relic either. This past year, Presidents Kim and Xi exchanged friendly public letters marking the 55th anniversary of the treaty. Some in China have called on China to terminate the DPRK defense treaty, but a selection of Chinese experts surveyed by the Chinese newspaper Global Times last year continued to support the treaty alliance despite growing reservations.
In the end, Chinese officials could always ignore their treaty obligations or choose to adopt an implausible interpretation to avoid getting involved in a U.S.-DPRK conflict. However, abandoning the treaty or failing to fulfill the treaty’s terms would not be costless for the Chinese leadership’s reputation at home or abroad. U.S. analysts should keep this in mind when weighing China’s all-important reaction to any U.S. strike on North Korea.