Abroad, the widely noted aspect of Barack Obama’s re-election victory was its social and class character. The president was re-elected by a majority of American minorities. He won 93 percent of the African-American vote, which is hardly surprising, but also 71 percent of the Hispanic electorate, while his part of the white active electorate diminished about 10 percent from the share he carried four years ago.

This is an inevitable result of the steady ethnic diversification of the American population and the increasing incidence of inter-ethnic or interracial marriage, with a consequent diminishment of the originally dominant Caucasian component in the make-up of the population of the United States, and of the historical culture that the founders possessed.

The much-cited white Anglo-Saxon Protestant American is proportionately a dwindling race, even as the non-Protestant and even non-Anglo-American whites of European origin — Irish, Slav, Scandinavians, French, Italians, etc. — have made their way into what has in the past been presumed the ruling class or caste. From “huddled masses yearning to breathe free,” to the Kennedy School at Harvard, and on to Wall Street and Washington.

These recruits to the elite want to play the part. Why not? But which part, the moral? The historical? In the aggregate, the aspirations of the new arrivals on the corporate, Wall Street and even government scene seem plausibly portrayed in the photos that appear in Ralph Lauren clothing and home furnishings advertisements in glossy magazines — beautiful people with vacant faces in beautiful homes, with vintage cars at the door and lolling pedigreed hounds. All wreathed in power.

American establishment liberals are inclined to approve what seems an objectively just and politically progressive phenomenon of social ascension, although not currently accompanied by increasing equality, social justice, fraternity, etc., among the changing and vastly enlarged American population — most of it poor, today, or in straitened circumstances.

Conservatives are — shall we say — inclined to regret what has changed, without saying so. But it has been corporate America and Big Agriculture that promoted indiscriminate and often illegal immigration, in order to provide cheap agricultural and industrial labor, to break trade and industrial unions, and to provide servants and household help for the upper and middle classes. (The bosses certainly did not expect such people to become voters; it was only in the closing days of the campaign that Mitt Romney realized that he should be nice to new immigrants and their children, but it seems to have proven too late).

For good or bad, the United States has changed with dazzling speed. I grew up in a white population all but entirely of European origin. My mother was a member of the Daughters of the American Revolution. I went to racially segregated public schools in segregated neighborhoods with segregated friends. I was at my university when the first black student was nervously admitted. I trained for the Korean War in an Army in the midst of its own racial desegregation (three years after President Harry S. Truman had ordered this, and under pressure of the severe manpower losses suffered during the initial weeks of the war).

Now we have elected for a second term a black American president, in a country composed of a multitude of colors and races and inheritances. No wonder folks down home don’t like what has happened. But it’s their country, and we Americans did it to ourselves — like it or not.

A large part of the new population has only the faintest idea of how the United States came about. (The same is probably true of today’s “old” population.) A French newspaper columnist wrote the morning after the election (in praise of American civic spirit) that all American children “memorize the Constitution” in primary school. I imagine he had the Declaration of Independence in mind, but he was wrong there, too. American schoolchildren (unlike French schoolchildren) do not memorize anything in school beyond nursery rhymes (and the Pledge of Allegiance to the flag, as congressionally mandated, which usually is recited as an unintelligible gabble).

Is this vast new America actually governable? It hasn’t been for the last four years. Pundits say that the system has broken down. It has. Is the breakdown irreparable? The newly elected President Obama says it is not.

He speaks after a presidential campaign profoundly corrupted by moneyed interests, vindictiveness and hatred. This is not unprecedented, as American history attests. His words nonetheless have to be taken as a conditional reassurance. He said in his victory speech that there are “bonds that hold together the most diverse nation on Earth — the belief that our destiny is shared; that this country only works when we accept certain obligations to one another, and to future generations … and among those are love and charity and duty and patriotism.”

The conditions will be tested, as never before, during the next four years.

Visit William Pfaff’s Web site for more on his latest book, “The Irony of Manifest Destiny: The Tragedy of America’s Foreign Policy” (Walker & Co., $25), at www.williampfaff.com.