...On balance, immigration is not only good, but critical, for this country and this economy. But like most things in life, it creates winners and losers. And the preponderance of evidence indicates that the flood of illegal immigrants has hurt those on the bottom of the economic ladder most, blacks in particular and probably even American-born Hispanics.

George Borjas, an economist at Harvard's Kennedy School of Government, is one of the leading scholars in the field. His research, drawn from 40 years of census data, has found "a strong correlation between immigration and black wages, black employment, and black incarceration rates." In an interview yesterday, Borjas was careful to say that the majority of the huge job losses in the black community would have occurred even if a single immigrant had never crossed the border. But he attributed somewhere between 30 and 40 percent of the job losses among low-skilled blacks to immigration...

...Northeastern University economist Andrew Sum has come to much the same conclusion. In the years 2000 to 2005, Sum found, 85 of every 100 net new workers in the country was a new immigrant. Among just men - native-born Americans and immigrants here more than five years - the net employment growth was "less than zero," Sum reported. Less than zero is a very small number.

While the job gains have overwhelmingly gone to new immigrants, Sum found that African-Americans and American-born Hispanics were big losers. The employment rates among black men ages 16 to 19 dropped 20 percent over five years and 24 percent among Hispanic male teenagers. In almost every category, the young and undereducated, whites included, lost ground...