Gordon Crovitz, in a recent Wall Street Journal op-ed, pointed out some statistics.
The Congressional Budget Office last year estimated that legalizing the 11 million undocumented immigrants would boost federal revenues by $48 billion over 10 years while costing $23 billion in public services. Adding more skilled workers would bring in $100 billion over a decade, mostly from increased income taxes.
In addition to this, I add (and reiterate) immigrants start more businesses than Americans who’ve been here for two or three or more generations. Those businesses employ people, and more so than “just” immediate family members.
There’s also the demographic question: the Unites States has only just returned to a birth rate that even barely replaces our death rate. We need immigration for continued population growth; we don’t want to face the population implosion risk from aging that Russia, the People’s Republic of China, the Federal Republic of Germany, France, and lots of other nations are facing. When Social Security was enacted, there were seven workers to contribute to the SS payments for every retiree, and that retiree had a retired life expectancy of some five to seven years. Today there are three workers per retiree, and that retiree has a retired life expectancy of nearly fifteen years. If we don’t intend to change the structure of Social Security, we need immigration.