U.S.-born workers are climbing the educational ladder, acquiring interactive/analytic skills and progressively leaving the manual jobs that would put them in competition with immigrants. If the trend continues as expected, the day is not far off when virtually all manual labor will be performed by foreign-born labor. This implies large wage gains for native workers, since they will be able to specialize in language-intensive and interactive tasks that are typically far better paid.

While some people shudder at the prospect of a more stratified society with immigrants at the bottom, keep in mind that the biggest gainers by far in this situation are the immigrants themselves.[America’s Stake In Immigration—Why Almost Everybody Wins (PDF)]

Right, our current immigration system is the perfect policy for Lake Wobegon, where all the children are above average. For the real America, where half the kids are below the median in book smarts, not so much