In the context of the Self/Other nexus in critical International Relations (IR) studies, this article aims to interrogate Pyongyang's ways of constructing (North) Korean nationalism which is integral to its regime security and state policy in the 2000s. Toward this end, focusing on Pyongyang's ardent "National Cooperation (Minjok Gongjo) Discourse" toward South Korea, this article reveals North Korea's state identity concealed in the Discourse and then problematizes the Discourse's modes of securing that state identity in pursuit of Pyongyang's regime legitimacy in the Korean Peninsula. In so doing, this article addresses the question of how, through the rendering of South Korea vis-a-vis North Korea, the National Cooperation Discourse as one of North Korea's state policies has helped produce, reproduce, and police North Korea's state identity which is supposedly behind its behavior toward itself, South Korea, and the outside world.