The following is from Samuel Huntington's 1993 essay in Foreign Affairs in reply to criticism of his 1991 essay.
What follows next is from a Brookings Institution study:
One function of a paradigm is to highlight what is important (e.g., the potential for escalation in clashes between groups from different civilizations); another is to place familiar phenomena in a new perspective. In this respect, the civilizational paradigm may have implications for the United States. Countries like the Soviet Union and Yugoslavia that bestride civilizational fault lines tend to come apart. The unity of the United States has historically rested on the twin bedrocks of European culture and political democracy. These have been essentials of America to which generations of immigrants have assimilated. The essence of the American creed has been equal rights for the individual, and historically immigrant and outcast groups have invoked and thereby reinvigorated the principles of the creed in their struggles for equal treatment in American society. The most notable and successful effort was the civil rights movement led by Martin Luther King, Jr., in the 1950s and 1960s. Subsequently, however, the demand shifted from equal rights for individuals to special rights (affirmative action and similar measures) for blacks and other groups. Such claims run directly counter to the underlying principles that have been the basis of American political unity; they reject the idea of a "color-blind" society of equal individuals and instead promote a "color-conscious" society with government-sanctioned privileges for some groups. In a parallel movement, intellectuals and politicians began to push the ideology of "multiculturalism," and to insist on the rewriting of American political, social, and literary history from the viewpoint of non-European groups. At the extreme, this movement tends to elevate obscure leaders of minority groups to a level of importance equal to that of the Founding Fathers. Both the demands for special group rights and for multiculturalism encourage a clash of civilizations within the United States and encourage what Arthur M. Schlesinger, Jr., terms "the disuniting of America."
The United States is becoming increasingly diverse ethnically and racially. The Census Bureau estimates that by 2050 the American population will be 23 percent Hispanic, 16 percent black and 10 percent Asian-American. In the past the United States has successfully absorbed millions of immigrants from scores of countries because they adapted to the prevailing European culture and enthusiastically embraced the American Creed of liberty, equality, individualism, democracy. Will this pattern continue to prevail as 50 percent of the population becomes Hispanic or nonwhite? Will the new immigrants be assimilated into the hitherto dominant European culture of the United States? If they are not, if the United States becomes truly multicultural and pervaded with an internal clash of civilizations, will it survive as a liberal democracy? The political identity of the United States is rooted in the principles articulated in its founding documents. Will the de-Westernization of the United States, if it occurs, also mean its de-Americanization? If it does and Americans cease to adhere to their liberal democratic and European-rooted political ideology, the United States as we have known it will cease to exist and will follow the other ideologically defined superpower onto the ash heap of history.
The U.S. will become “minority white” in 2045, Census projects
New census population projections confirm the importance of racial minorities as the primary demographic engine of the nation’s future growth, countering an aging, slow-growing and soon to be declining white population. The new statistics project that the nation will become “minority white” in 2045. During that year, whites will comprise 49.9 percent of the population in contrast to 24.6 percent for Hispanics, 13.1 percent for blacks, 7.8 percent for Asians, and 3.8 percent for multiracial populations....
Among the minority populations, the greatest growth is projected for multiracial populations, Asians and Hispanics with 2018–2060 growth rates of 175, 93, and 85 percent, respectively. The projected growth rate for blacks is 34 percent.* The demographic source of growth varies across groups. For example, immigration contributes to one-third of Hispanic growth over this time span, with the rest attributable to natural increase (the excess of births over deaths). Among Asians, immigration contributes to three quarters of the projected growth.