Do Chemical Weapons Threaten US Extended Deterrence in Asia?

If the U.S. doesn’t respond to Syria’s chemical weapons use, will its Asian allies doubt its commitment to them?

Prior to President Obama’s decision to delay the Congressional vote on military intervention in Syria, top administration officials told Congress that a failure to punish Bashar al-Assad’s chemical weapons use would reverberate with allies in East Asia.

"North Korea is hoping for ambivalence from the Congress," Secretary of State John Kerry told the House Foreign Affairs Committee last week. Similarly, Secretary of Defense Chuck Hagel suggested that South Korea was gravely concerned about the North’s WMD capacity, and argued that the DPRK could be emboldened to use chemical weapons if the U.S. failed to uphold the norm of chemical weapons non-use.

With military action on “pause” as the administration evaluates the prospects of a chemical weapons handover by Assad, it is worth contemplating this question: If the United States fails to take punitive action against Syria for chemical weapons use, will allies (and South Korea in particular) doubt the United States’ commitment to defend them from the same?

On one hand, there is a strong case to be made that Syria and South Korea are apples and oranges: A decision not to intervene militarily to uphold an internationally accepted chemical weapons taboo hardly suggests that the United States would fail to come to the aid of a close treaty ally if it were the victim of a chemical attack. Syria is not party to the Chemical Weapons Convention, and though it is a signatory to the Geneva Protocol, which outlaws the use of poison gas in interstate war, that treaty has no formal enforcement mechanism. The United States’ decision to intervene in Assad’s horrendous gassing of his own people would be out of a desire to reinforce a norm, rather than out of any specific, positive legal obligation.

Contrast this to the U.S.-ROK relationship. In 1953, the United States and South Korea signed a Mutual Defense Treaty, which states that an attack on either ally in the Pacific region will be treated as a threat to the peace and security of the other. Since that document was signed, the United States has deployed tens of thousands of troops on South Korean soil, participated in a joint military command structure with its ally, and coordinated action to respond to countless provocations by North Korea. Moreover, in recent years, as the United States has reduced the role of nuclear weapons in its overall deterrence posture, it has taken great care to account for South Korea’s concerns about a chemical or biological attack from the North. The 2010 Nuclear Posture Review strengthened its negative security assurances and circumscribed the United States’ willingness to use nuclear weapons to respond to chemical or biological attacks unless the attacker possessed nuclear weapons and was out of compliance with its NPT (read: North Korea). The United States has therefore retained the right to respond to a chemical attack on South Korea from the North using nuclear weapons. Given this forceful and carefully crafted declaratory policy, it is difficult to imagine that Washington would ever abandon Seoul if it were the victim of a brutal gas attack.

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On the other hand, the decision-making process over intervention in Syria has proceeded in a way that may be deeply disquieting to allies, treaties and declaratory policies aside. The President’s decision to turn to Congress “in the absence of a direct of imminent threat,” suggests that the United States may delay military action even if the Commander-in-Chief deems it necessary. While, once again, South Korea is no Syria, the credibility of U.S. security guarantees not only requires the United States to convince its allies that it will provide them with military support, but that it will do so promptly in their hour of need. In an age of massively destructive weapons and long-range delivery vehicles, these promises have generally been associated with the centralization of war powers in the executive branch. The decision to pause to consider Congress’s views may stoke allies’ fears that their security could be held hostage to checks and balances. Indeed, most of the United States’ defense treaties state that it will “act to meet the common danger in accordance with its constitutional processes.” In the last week and a half, said constitutional processes can’t look pretty if you’re sitting in Seoul.

Given the often-cacophonous messaging of the last several weeks, assurances to treaty allies like South Korea must be made clear. Specifically, the U.S. should state clearly that an attack on its allies, be it conventional, chemical, or anything else, is an “imminent threat,” and that protecting them is a vital U.S. interest. Whether or not North Korea is hoping for ambivalence, the South should get nothing of the sort.