Samuel P. Huntington
| It doesn't stop|
at the water's edge
Samuel P. Huntington (1927-2008) was a highly respected (we don't know why) political scientist in the United States, and the person who popularized the infamous term "clash of civilizations," first in a 1993 article in Foreign Affairs, and then as a book in 1996, to try to predict how the post-Cold War world would pan out. It has to be noted, though, that Huntington's original Foreign Affairs article was written as a response to Francis Fukuyama's Panglossian ideas about the End of History (first in a 1989 article in The National Interest, later expanded into the 1992 book The End of History and the Last Man).
 Clash of Civilizations
Huntington proposed the notion that the world could be divided into nine more or less self-conscious civilizations, separated by cultural fault lines. These nine civilizations were: Western, Islamic, Buddhist- except that the Buddhist bloc doesn't really matter-, Sinic, Japanese (sorry, little guy), Hindu, Slavic/Orthodox, Latin American, and
Black non-Islamic, sub-Saharan African plus majority-African-descended Latin American countries.
Critics of the theory have pointed out how close certain nations with different cultures have been. For example, the United States, Turkey, and Israel all have had close relationships in the past, in spite of the fact that the US is Western, Turkey is Islamic, and Israel, a supposed "lone state." However, proponents of the theory point out how relations between Israel and Turkey have rapidly deteriorated in the post-Cold War world and are now extremely hostile. Turkey has transitioned from a secular state to an Islamic theocracy largely on cultural grounds. Additionally, previously strong Cold War relations between the United States and Pakistan have completely collapsed to the point that the US was afraid that the Pakistan government would assist Osama bin Laden in the famed Seal Team 6 assassination.
Although clustered cultural groups, or "civilizations," have not historically been self-conscious units, are not homogenous, and are not easy to draw lines between, the major aspect of Huntington's theory is that civilizations will become self-conscious units. The European Union arguably reflects this reality. An additional prediction of the theory is that religious identity, to the extent that it relates to culture, will become much more important in decided international alliances. To Huntington's supporters, the attacks on Avijit Roy and others in Bangladesh, and the intensity of headscarf debates in Albania, demonstrate that Muslim-dominated societies are developing a collective cultural identity, in spite of historically dramatic differences between them. As a result, secular majority-Muslim nations are experiencing an identity crisis.
Some "moderate" supporters of Huntington's theory argue that while Huntington's major thesis was correct, i.e., cultural divisions are replacing politically-philosophical divisions as the predominant criteria for international alliances, they also argue that Huntington classified the civilizations incorrectly. Instead, they would use clustering methods, similar to the ones used in genetics, rather than mere religious and historical identity. Such methods would arguably make some majority-Muslim countries, such as Albania, "Western" rather than "Islamic." Even with clustering methods, some small nations like Singapore straddle multiple civilizations and don't fit neatly into any category. Finally, it must be said that Korea should definitely not be classified as "Sinic"(Chinese) as Huntington had originally done. Korea is difficult to classify, and since North Korea and South Korea have become so incredibly different, one could argue that South Korean civilization is distinct from North Korean "civilization"(if you can call North Korea civilization.) Since the Korean people were only ever independent and unified simultaneously for brief periods of time(see Gogoryeo and Silla,) it makes sense that they would diverge.
One major prediction of Huntington's theory that appears to be coming true gradually is the decreased lack of interdenominational fighting between religions. Northern Ireland has become quite peaceful, and Catholics have risen rapidly within the Christian Conservative circles, something that was unthinkable in the days of Al Smith and William Jennings Bryan. Additionally, the rise of "neo-Conservatism" was marked by its dramatic inclusion of Jews into right-wing political circles and the increased identification of Israel as a Western country. Critics of Huntington point out that his lumping in Iran and the Arab states in a single Islamic civilization is odd because Iran is not only the largest and most powerful Shi'a state, it's also Persian, not Arabic, which is yet another reason why Wahhabis, Salafists and other Sunni Islamists consider Iran to be among their greatest enemies. Huntington's theory predicts either that the tensions between Iran(Shia) and ISIS(Sunni) will dramatically subside(doesn't seem too likely,) or that Shia Islam will acquire a distinctly Persian identity and separate from its Arabic roots, as Christianity largely separated from its originally Middle-Eastern identity.
 Who Are We? The Challenges to America's National Identity
This is the 2004 book of Huntington's that nobody wants to talk about because he shows his true nativist, xenophobic colors. He gets really scared that
the Mexicans are coming to take urr jerrrrbs Latino Catholic immigrants who are, of course, lazy might not be able to integrate with us good hard-working White Christian folk into America's Protestant Anglo-Saxon culture. Did we mention he had the book published in 2004? Nonetheless, Huntington's theory could be used to predict the political tensions at Live Oak High School where students were only allowed to display Mexican flags on Cinco de Mayo despite the fact that Cinco de Mayo is not even celebrated much in Mexico.
However, the bulk of the evidence  suggests a reasonably significant degree of Latin American assimilation within three generations so it is quite possible that Huntington's theory does not accurately predict what is actually happening. Either way, many factors would need to be considered in order to critically evaluate Huntington's theory that immigration from Latin America would cause the United States of America to identify less with the general Western Civilization and more with Latin American civilization. One possibility is that Latin America is becoming more like the rest of Western Civilization, and these changes explain the relative ease of assimilation. Another possibility is that America's social infrastructure is actually better at assimilation than is commonly believed. The third, and most counter-intuitive possibility, is that immigrants from Latin America generally want to assimilate into American culture. Currently, there is not enough evidence to test Huntington's theory in this way.