The United States has reportedly been debating whether to "react to some nuclear or missile test with a targeted strike against a North Korean facility to bloody Pyongyang’s nose and illustrate the high price the regime could pay for its behavior." This article asks a simple question: would such a “bloody nose strike” (BNS) violate the jus ad bellum?
Providing a coherent answer is complicated by the lack of clarity surrounding the United States’ planning. In particular, the U.S. government has not specified what kind of provocation it believes would justify launching a BNS, has not identified precisely what a BNS would entail, and has not offered a legal theory for why a BNS would be permissible under international law.
Because so much is unknown, the following legal analysis proceeds on two assumptions. The first is that the United States would justify a BNS either as the collective self-defense of Japan or on the basis of its own individual right of self-defense. The second is that a BNS would be a response to either a test of a nuclear weapon on North Korean territory or the intentional launch of an unarmed ballistic missile into Japan’s territorial waters.
The article is divided into five parts. Part I provides a brief introduction. Part II asks whether either North Korean provocation would qualify as an "armed attack," the necessary precondition of individual or collective self-defense. Part III analyzes what would be required for the United States to justify a BNS as the collective self-defense of Japan. Part IV discusses whether the United States could justify a BNS as its own individual self-defense and Part V concludes.