RE: American Worker
This seems like an incredibly simplified way to approach the issue. What isn't stated in the 1.5 million figure is the number that have advanced degrees in fields such as computer science, engineering, medicine, etc... Such imports fill positions that require immigration to meet domestic needs. Personally, I think its better to have a foreign engineer residing in America--where they will pay taxes and contribute to our economy--than in India or China, promoting outsourcing. Additionally, these highly-skilled workers actually create jobs. An engineer who designs a new products creates jobs: secretaries, product testers, factory workers, people to market the product, etc... Frankly, as I've said in the past, we should be increasing the influx of these workers.
The issue of the unskilled workers is open for more debate. There certainly is overlap with many American workers, particularly those most likely to make minimum wage, but I think this is in large part a function of minimum wage restrictions...and is more than I want to type about now.