From Amitai Etzioni, an excellent critique of of the late Samuel Huntington's ideas (including, most recently and noxiously, that Mexican immigrants are destroying our "shared American identity"):

The theme that runs throughout Huntington's various works is best characterized as a theory of fear. His books typically identify a mounting threat, such as Mexican immigrants, Islamic civilization, or democratic proclivities, and then point to the need for strong national-unity building measures and mobilization of the people (including militarization) in response to the barbarians at the gates.

....

It is not only empirically wrong but also psychologically troubling and strategically counterproductive to approach the world from an "us versus them" perspective and to hold that we bring light to the world through enlightenment, rationality, and democracy, while "they" are the force of darkness, the evil empire. A much more valid and healthier approach is to recognize that there are major moderate and fundamentalist camps in all civilizations and that the West should work with moderates everywhere and be on its guard against fundamentalists--everywhere. The West should also recognize that just as it brings to the world concerns of human rights and liberty, other civilizations also bring to the world valuable concerns that the West has increasingly neglected, for instance those of the common good and community.