From a 10,000 foot level there are only two primary drivers of economic growth - increases in population, and improvements in productivity. A recent study by the conservative think tank the American Enterprise Institute shows how immigration pulls both of these economic levers.... http://www.fiercehomelandsecurity.com/story/aei-study-immigrants-boost-employment-us-natives/2012-01-04
A typical counter-argument is that the only immigrants worth keeping are those who come for advanced degrees because the much larger pool of less educated immigrants may add to economic output in some areas but this benefit is negated by a higher than national average rate of public assistance going to newcomers. They do participate in welfare programs at a higher rate - 21% of immigrants versus 16% of native born. But they pull themselves out of poverty unlike many native born Americans - the poverty rate of Americans overall is roughly 12% while foreign born is 17%...but for immigrants here 20 years or longer the poverty rate is 9%, significantly less than the national average.
Many are calling for a return to traditional American values use that as an excuse to put up fences. But in reality we should be doing everything we can to encourage immigration. With babyboomer retirement accelerating and life expectancy climbing, we need all the help we can get. When Japan's birth rate slowed below the replacement rate, that country faced 20 years of stagnation. The same problem will be a significant headwind to rapid growth in China as soon as the one time benefit of urbanization have been accrued. http://www.bloomberg.com/news/2012-01-04/china-no-country-for-old-men-as-demographic-tsunami-begins.html The lessons are there for the learning and the data is clear - immigration is good - it is also arguably THE core 'American value.'