The fallacy is to assume that since play tough policy didn’t seem to work with NK, hence, cooperative policy should have worked. More likely, it’s the other way around that happened. Cooperative diplomacy couldn’t work, hence we have to play tough, which is just another facet of diplomacy. You don’t see anyone jumping to the 6 parties talk suggestion last week, do you???
Which party you belong to usually don’t have much influence on American diplomacy. I don’t like Bush, but I don’t blame him for the crazy North Korea’s actions or the American’s change of way to deal with NK.
The presence of American troops in SK is to protect South Korea from an aggressive north (a proven aggressor). The South Korean people need the presence of American power to protect them from the NK and China.
North Korea is the East German of China, some Chinese officials said in the past. Not a perfect analogy, but the fact is that China will never stand to let the Koreas to be unified because of its importance to China. China does not need to have troops in North Korea, it already achieved influence on the leadership of NK who depends on China for its survival while NK is playing its role very well for China.