Americans expect Seoul to play good cop to their bad cop. They assume the commonality of language, ethnicity and culture will help the South build trust with the North, so it can put the alliance's demands over more persuasively. They also reckon the North Koreans will find it easier to yield to soft-spoken fellow Koreans than to the foreigners with whom they have been exchanging threats and insults for decades. But to play such a role the South must overcome an exceptionally high barrier of mistrust. It gets no brownie points for Koreanness alone. On the contrary; from the North's standpoint it's precisely that co-ethnicity which makes the puppet state's long collusion with the Yankees so heinous.