Throw a batch of more data onto the debate. This time, it's a University of California at Davis economist who concludes that immigrants actually help increase - not decrease - the wages of native-born Californians. Giovanni Peri called his findings "remarkable" because it contradicts previous research. Between 1990 and 2000 alone, when new immigrants accounted for a 20-percent increase in California's employment, the average real wages of native workers in California rose by 4 percent. From the Sacramento Bee, which had the story this afternoon:

Immigrants with low levels of education are not competing with natives who are highly skilled, Peri said. He also said immigrant labor spurs the economy and boosts demand for natives to step into jobs that require more skill - even if it's the ability to speak English, including work as supervisors or more complex tasks. He cited construction work as an example. "Natives come up and make supervisors," he said. "This shields them from the wage impact."