Overall, immigration has been a net gain for existing American citizens, though a modest one in proportion to the size of our 13 trillion-dollar economy.
Immigrants do not take American jobs. The American economy can create as many jobs as there are workers willing to work so long as labor markets remain free, flexible and open to all workers on an equal basis.
Immigration in recent decades of low-skilled workers may have lowered the wages of domestic low-skilled workers, but the effect is likely to be small, with estimates of wage reductions for high-school dropouts ranging from eight percent to as little as zero percent.
While a small percentage of native-born Americans may be harmed by immigration, vastly more Americans benefit from the contributions that immigrants make to our economy, including lower consumer prices.
From a letter to President Bush signed by many economists, both right and left and posted at Marginal Revolution.