You're suggesting there isn't an ideology moving the US government? Every country has an ideology, a doctrine or something like that, and independently of the sheer number and diversity of its population, what's ALWAYS discussed when someone mentions a country is its government and its policies, including foreign policies. You're bringing a no true Scotsman to the table, which is a fallacy. From its foreign policy on Vietnam, the US does not seem to "give a shit" as the OP said.