Speaking to the Hispanic Chamber of Commerce in Albuquerque in 2001, George W. Bush declared that, as Mexico was a friend and neighbor, “It’s so important for us to tear down our barriers and walls that might separate Mexico from the United States.” Bush succeeded. And during his tenure, millions from Mexico exploited his magnanimity to violate our laws, trample upon our sovereignty, walk into our country, and remain here. In 2007, backed by John McCain, Hillary Clinton, Teddy Kennedy, and Barack Obama, Bush backed amnesty for the 12 million people who had entered America illegally. The nation thundered no. And Congress sustained the nation.

The latest mass border crossing by scores of thousands of tots, teenagers, and toughs from Central America has killed amnesty in 2014, and probably for the duration of the Obama presidency. Indeed, with the massive media coverage of the crisis on the border, immigration, legal and illegal, and what it portends for our future, could become the decisive issue of 2014 and 2016.

But it needs to be put in a larger context. For this issue is about more than whether the Chamber of Commerce gets amnesty for its members who have been exploiting cheap illegal labor. The real issue: Will America remain one nation, or are we are on the road to Balkanization and the breakup of America into ethnic enclaves? For, as Ronald Reagan said, a nation that cannot control its borders isn’t really a nation anymore.

In Federalist No. 2, John Jay wrote,

Providence has been pleased to give this one connected country to one united people — a people descended from the same ancestors, speaking the same language, professing the same religion, attached to the same principles of government, very similar in their manners and customs …

He called Americans a “band of brethren, united to each other by the strongest ties.” The republic of the founders for whom Jay spoke did not give a fig for diversity. They cherished our unity, commonality, and sameness of ancestry, culture, faith, and traditions. We were not a nation of immigrants in 1789.

They came later. From 1845-1849, the Irish fleeing the famine. From 1890-1920, the Germans. Then the Italians, Poles, Jews, and other Eastern Europeans. Then, immigration was suspended in 1924.

From 1925 to 1965, the children and grandchildren of those immigrants were assimilated, Americanized. In strong public schools, they were taught our language, literature, and history, and celebrated our holidays and heroes. We endured together through the Depression and sacrificed together in World War II and the Cold War. By 1960, we had become truly one nation and one people.

America was not perfect. No country is. But no country ever rivaled what America had become. She was proud, united, free, the first nation on earth. And though the civil rights movement had just begun, nowhere did black peoples enjoy the freedom and prosperity of African-Americans.

Attorney General Eric Holder said Sunday that America is today in “a fundamentally better place than we were 50 years ago.” In some ways that is so. Equality of rights has been realized. Miraculous cures in medicine have kept alive many of us who would not have survived the same maladies half a century ago.

But we are no longer that “band of brethren.” We are no longer one unique people “descended from the same ancestors, speaking the same language, professing the same religion.” We are from every continent and country. Nearly 4 in 10 Americans trace their ancestry to Asia, Africa, and Latin America. We are a multiracial, multilingual, multicultural society in a world where countless countries are being torn apart over race, religion, and roots.

We no longer speak the same language, worship the same God, honor the same heroes or share the same holidays. Christmas and Easter have been privatized. Columbus is reviled. Stonewall Jackson and Robert E. Lee are out of the pantheon. Cesar Chavez is in. Our politics have become poisonous. Our political parties are at each other’s throats. Christianity is in decline. Traditional churches are sundering over moral issues like abortion and same-sex marriage. Islam is surging.

Our society seems to be disintegrating. Over 40 percent of all births now are illegitimate. Among Hispanics, the figure is 52 percent. Among African-Americans, 73 percent. And among children born to single moms, the drug use rate and the dropout rate, the crime rate and the incarceration rate, are many times higher than among children born to married parents.

If a country is a land of defined and defended borders, within which resides a people of a common ancestry, history, language, faith, culture, and traditions, in what sense are we Americans one nation and one people today? Neocons say we are a new kind of nation, an ideological nation erected upon a written Constitution and Bill of Rights. But equality, democracy, and diversity are not mentioned in the Constitution. As for what our founding documents mean, even the Supreme Court does not agree.

More and more, 21st-century America seems to meet rather well Metternich’s depiction of Italy—”a geographic expression.”

Patrick J. Buchanan is the author of the new book “The Greatest Comeback: How Richard Nixon Rose From Defeat to Create the New Majority.” Copyright 2014 Creators.com.