Well no - not even Bush believed in that load of crap. What they did believe though is that a war has to pay for itself, and then some (notice how as soon as the construction contracts were removed from American firms in Iraq and Afghan, pull outs were scheduled?)
Aside from endangering the lives of the US soldiers there, the US throwing this story around is futile. More likely it actually came from North Korea itself as a hint to China to give them a hand. Actually, the state of that country, it is highly likely that it is true. They are all fucking nuts.