"In 376 a large band of Gothic refugees arrived at the Empire's Danube frontier, asking for asylum. In a complete break with established Roman policy, they were allowed in, unsubdued. They revolted, and within two years had defeated and killed the emperor Valens -- the one who had received them -- along with two-thirds of his army, at the battle of Hadrianople."

So writes Oxford's Peter Heather in "Fall of the Roman Empire: A New History of Rome and the Barbarians," who is convinced that Valens' welcoming of the Goths was the decision that sealed the fate of the empire.

As recent headlines tell us of 5 million more immigrants having arrived in America in the last five years, we see now, no longer as through a glass darkly, how America ends.

There are 36 million immigrants here, a number almost equal to all who ever came from Jamestown in 1607 to JFK. We are host to more illegal aliens, 12 million, than all the Jews, English and Irish who came over 400 years.

In George W. Bush's tenure, 6 million intruders have been caught on our Southern border breaking in. One in 12 had a criminal record. Behind them, waiting to see if Bush will grant amnesty or secure the border, are the world's 4 billion to 5 billion people whose average income is less than that of Mexico.

Last year, 155,000 OTMs ("other than Mexicans"), triple the number of 2003, from Latin America, the Middle East, Africa and Asia were caught. Four of five never appeared in court. They vanished into our midst.

These numbers are astronomical by any historical standard, and the mindset of many newcomers is not that of the Ellis Island generation. On May 1, almost a million Hispanics marched under Mexican flags through Los Angeles to demand the rights of U.S. citizenship for all illegals. Aerial shots revealed huge signs reading, "This is Our Land," and, "Chicano Power" In Mexico City, PAN party members marched beside communists and Subcommandante Marcos in solidarity with their kinsmen in America.

"With all due respect to Uncle Sam," declaimed one Mexican TV reporter, "this shows that Los Angeles has never stopped being ours."

Added the respected Mexican pundit Sergio Sarmiento, if Mexicans "have begun the reconquista of the territory that the United States took by force from Mexico between 1835 and 1848, they have been able to do this thanks to the fact that the Americans themselves have permitted it."

And so we have. In 1994, Californians sought to slow the invasion with Proposition 187, restricting welfare to U.S. citizens and legal aliens. After 187 won in a landslide, a federal judge threw it out. "Art" Torres, chairman of the California Democratic Party, exulted, "187 was the last gasp of white America in California."

So it appears to have been.

In the '90s decade, for the first time since the Spanish arrived, the white population of California fell. Native-born Californians are heading over the mountains back to the lands whence their ancestors came. By ethnic origin, California and Texas are already Third World states. Hispanics alone account for 25 percent of the population of Arizona, 34 percent of California and Texas, 43 percent of New Mexico, and growing shares of the population of Nevada, Colorado and Utah, all states carved out of Mexico.

Moreover, ethnic chauvinism is rampant in the barrios. As in the movements of Evo Morales in Bolivia and Ollanta Humala in Peru, barrio talk in America is increasingly about "indigenous peoples" and "European occupiers." A black-brown war has broken out among the underclass in Los Angeles. Three in five Mexicans now believe the Southwest is stolen land that belongs to Mexico.

By 2050, the Census Bureau estimates 102 million Hispanics will live in America, heavily concentrated in the Southwest. The ethnic, linguistic and cultural reconquest of the American Southwest by Mexico is well advanced.

As I write in my new book, "State of Emergency: The Third World Invasion and Conquest of America," George Bush may go down in history as the man who not only lost the magnificent lands won for America by James Polk, but, by refusing to do his duty and halt this invasion, ensured the Balkanization and dissolution of his country.

Not to worry, we are told. The Melting Pot will work its magic. In a generation, the scores of millions who have come here will be assimilated and Americanized, as were the millions who came to Ellis Island.

The hope is delusional. The Melting Pot is broken. Our elites want it smashed forever. They no longer believe in assimilation -- they worship at the altar of diversity. And millions of aliens are adamant about retaining their own language, culture, identity and allegiance to the mother country, not the United States.

The "hyphenated-Americanism" Teddy Roosevelt and Woodrow Wilson decried is today celebrated. On California's campuses there are separate dorms, fraternities, sororities, student centers and graduations for Asian, Hispanic and black students. The tens of millions coming endlessly from countries, cultures and civilizations whose peoples have never before been assimilated into a First World nation may spell the end of America as one nation and one people by mid-century. Why are we taking this risk?