When considering how South Korea will respond to the sinking of one of its naval vessels in disputed waters near North Korea, most commentaries stress the lack of military options. In contrast, Ralph Cossa [“Cheonan Incident: Choosing an Appropriate Response” PacNet #21] calls for a United Nations Security Council Resolution mandating that all North Korean submarines and torpedo-carrying boats be restricted to port. Recognizing that the chances of the UNSC passing such a resolution are slim to none, Cossa recommends the United States and South Korea sink North Korean submarines that leave port, and threaten to bomb submarine bases on the North Korean coast. If an international investigation underway into the cause of the Cheonan’s sinking indeed concludes that North Korea is responsible, it is important to focus minds on maintaining credible deterrence vis-a-vis Pyongyang. Ultimately, however, it is necessary to pursue a middle course between “turning the other cheek” and moving toward a hot war in the Yellow Sea.