South Korea's persistent enmity towards its erstwhile colonizer Japan has been a compelling topic of East Asian international relations scholarship for decades. This article argues that the historical evolution of South Korea's democracy offers a vital and overlooked piece of this puzzle. Given that it emerged from one of the most virulently anti-communist dictatorships of the Cold War period, in a society facing an ongoing threat from communist North Korea, any left-of-center opposition movement faced an uphill battle against severe anti-communism. In such circumstances, the only way for a leftist opposition party to survive was by pitting its stronger anti-Japan reputation against conservatives’ anti-communism. After South Korea's democracy stabilized, liberals tried and failed to overturn the anti-leftist institutions left over from the Cold War and then sought equilibrium through parallel rhetoric targeting pro-Japanese elements. Today, neither left nor right can afford to allow a final amicable settlement with its respective target of antagonism. Through analyses of domestic political rhetoric targeting alleged pro-Japanese or pro-communist elements, this paper demonstrates how these competing antagonisms achieved an uneasy equilibrium that undergirds South Korean political dynamics to this day.