What drives Korea-Japan security relations?

One of the most critical yet understudied security relationships in East Asia is that between the Republic of Korea and Japan. The problem faced by the United States throughout the Cold War was how to manage the volatile relations between these two allies, which by all objective standards looked ripe for cooperation-the two states shared common friends and enemies, trade complementarities and burgeoning economic opportunities, all tethered together at the top by a plethora of domestic-elite personal relationships. Three reasons have been offered over the years for the absence of good relations in spite of these forces for cooperation: economic competition, historical antagonism, and uncompromising political leadership in two "strong-state" regimes. The common theme resonating from all these views for international relations theory was the inability of material, external structural variables (i.e. realism) to explain this relationship; and the need for political scientists and area specialists to employ unit-level analyses-in particular, variables of a cultural, ideational, and identity nature to truly grasp the relationship. This article seeks to avoid the "food fight" of competing research programs by arguing for a synthetic approach as the most responsible way of understanding the US-Korea-Japan triangle. I contend that the incidents of cooperation and friction in relations stem from the "nesting" of material factors in ideational ones. In other words, historical antagonism and enmity are clearly the established negative templates that inform the relationship between Japan and Korea, but at certain moments during the Cold War era, compelling material forces (in particular, shared concerns about the strength of US security commitments to the region) have propelled outcomes in a direction entirely different from these cultural biases. Moreover, I argue that should such material forces be sustained for some time, the cooperation that can emerge between Japan and Korea will not only be episodic and expedient but will be robust and permanent, reflecting a positive transformation of these negative cultural and ideational templates. The one event that has the potential of effecting such a change in the future is unification.