Study: without immigrants, almost 2 million poorly educated Americans would be back in labor force.

The Center for Immigration Studies issued a report in March which estimates the negative impact of poorly educated immigrants upon the employment of poorly educated Americans. It finds a strong impact.
Dropping Out: Immigrant Entry and Native Exit From the Labor Market, 2000-2005” by Steven Camarota of the Center for Immigration Studies points to higher unemployment rates by industry and lower workforce rates of Americans, by age cohort. He estimates that without the increase in immigrant labor, amost 2 million Americans with a high school degree or less would be in the labor force.
He concludes in part:

The findings of this report call into the question the idea that America is desperately short of less-educated workers. In 2005, there were 3.8 million unemployed adult natives (18 to 64) with just a high school degree or less and another 19 million not in the labor force. Moreover, between 2000 and 2005 there was a significant deterioration in the labor market prospects of less-educated adult natives. The labor force participation has fallen significantly for both natives without a high school degree and those with only a high school degree. Had it remained the same in 2005 as it had been in 2000, there would have been an additional 450,000 adults without a high school degree in the labor force and 1.4 million more adult natives with a only high school degree in the labor force. This decline in particularly troubling because these workers already have lower labor force participation and higher unemployment than more educated workers. They also tend to be the poorest Americans.

Among teenage natives (age 15 to 17), labor force participation has also declined. At the same time that natives have been leaving the labor market, the number of immigrants with a high school degree or less in the labor force increased by 1.6 million. Wage growth among less-educated adult natives has also lagged well behind more-educated workers.