The debate over immigration: 200 years & counting: America may be a nation of immigrants, but we haven't always welcomed newcomers with open arms.

• Author: Roberts, Sam

"Few of their children in the country learn English." They "will never adopt our language or customs, any more than they can acquire our complexion."

A volley from today's heated debate over immigration? Not quite. That was Benjamin Franklin, worrying more than 200 years ago that German immigrants were overrunning his home state. "Why should Pennsylvania, founded by the English, become a colony of aliens, who will shortly be so numerous as to Germanize us instead of our Anglifying them?" Franklin wrote.

America's racial and ethnic makeup has been evolving since Spanish settlers and American Indians first mingled in the 16th century in St. Augustine and Santa Fe, in what are now Florida and New Mexico. But in spite of our heritage as a nation of immigrants, Americans have often been wary about welcoming foreigners, both legal and illegal.

AMERICA IN 1776

The fears raised by Franklin in the 18th century flared periodically in the 19th and 20th centuries. The debate has been rekindled today by concerns about national security, America's cultural identity, and the economic impact of an influx of low-paid workers, many here illegally from Mexico.

Of course, most Americans can trace their ancestry back Sam Roberts is urban affairs correspondent for The New York Times. to immigrants at some point. In 1776, most Americans were immigrants (or their descendants) from the British Isles. The majority were white Anglo-Saxon Protestants who came to escape religious or political persecution, or in search of economic opportunity.

But the population also included large numbers of Dutch, Spanish, and Germans, in addition to American Indians, whose ancestors came from Asia thousands of years ago, and blacks, who came involuntarily from Africa as slaves starting in 1619.

The first U.S. Census in 1790 counted nearly 4 million people, the majority of them of English, Welsh, or Scottish heritage; 757,000 blacks made up the next-largest group, followed by Germans.

Even then, some worried that immigration was a threat to the nation's character, and in 1790, Congress passed a that aliens who had lived in the U.S. for, two years could apply for citizenship--if they were "free white persons" and of good moral character.

The 19th century brought very different immigrants, starting with the Irish and Italians, who were both largely poor farmers and Catholic.

Beginning in 1845, a potato famine in Ireland, caused by a fungus which destroyed that country's most important...