I take issue with the Fuentes quote that the US understands itself. At least I do on a political level. Of course self-understanding can occur on different levels - political, social, psychological, etc. But because of the sheer political, economic and military clout of the US in the world I think most people - especially non-Americans - will take the question as applying on the political/economic level. Which is natural enough when people of any nation think about another nation. It's the first and most obvious way people of one nation relate to and understand those of another, whatever the power relations between the two.
Americans may have a good understanding of themselves in terms of national character or "personality" - what makes an American an American (what makes American writing distinctly American is one aspect of this question) - but from what I've observed I'd say they seem to have a pretty poor understanding of their nation in terms of its politics, internal and external, and how and why it acts on the global stage. The same could probably be said of how well the people of any nation understand their own politics. Again, it's the sheer stature and power of the US, and its constant forceful engagement with other countries all over the world - that is likely to give people of other nations a stronger view on how Americans understand the behaviour of their own country. When foreigners contrast how the US acts globally with what US politicians and media say about those actions, many foreign observers will naturally tend to assume that these statements reflect the general American view, and conclude that Americans as a people must be totally deluded about what their own country is doing abroad and why.
A number of prominent commentators (Chomsky comes to mind) have claimed that in fact many if not most Americans are quite aware of and informed about US politics, domestic and foreign, and are actually strongly opposed to what their government does at home and abroad. So maybe I contradict myself a little here. To the extent that what these commentators say is true - and that depends on how accurate are the sources they draw on for their assessment of the state of American public opinion - maybe I do agree with Fuentes.
Either way though, I think that as the US steadily turns itself into a surveillance and security state, as it relentlessly seeks military confrontations abroad, and as poverty and social inequality within the US become more and more breathtaking, the political self-awareness and dissent of the American people can only increase.
(Um, I just noticed the 250 word limit... sorry...)