Let me try to respond to some of the good comments, and clarify my position on others.
I tried to be clear that I would prefer the H-1B program be folded into a program that allows many more skilled immigrants to enter permanently. I do not believe workers under H-1B program are "exploited"-they do quite well economically- but they would have more commitment to this country if they were allowed in permanently.
Whatever are all the forces that determine earnings, immigration of many skilled workers will lower the wages of native-born skilled workers. There is no way around this fundamental proposition. Whether such immigration lowers these wages by a lot, however, does depend on the degree of substitutability of different classes of workers, how many fewer Americans train for these skilled jobs, and other factors. The other side of the story is that a larger number of skilled immigrants tend to raise, not lower, the wages of unskilled American workers.
It should have been clearer that I am not advocating eliminating unskilled immigrants, or even reducing the number of legal unskilled immigrants. I believe that many of them make important contributions to this country either directly or through their children and grandchildren. Perhaps even their numbers should increase-I am very pro-immigration. But I do believe that if for various reasons we are limited to taking a certain number of immigrants, then strong preference should be given to skilled immigrants for the reasons I cited, and for reasons given in several comments.
The story is told that the Premier of China was approached by one of his staff during the mid 1980‚Äôs who asked whether China should allow so many young persons to study abroad since they would not come back. His answer supposedly was China does not deserve to get them back if the environment cannot be made attractive enough for them to return. This is my view on the effects of so-called brain drains. Skilled workers do not return to Africa because economic and other conditions there are so dismal. As soon as China began to free its economy, and a little bit other freedoms, a much larger fraction of their students abroad decided to return. That is also the experience of South Korea, Taiwan, and many other countries.
But even without a large number of returnees, countries benefit on the whole from sending their students and skilled workers abroad. It is not only the remittances, but also the knowledge gained by those remaining from interactions with relatives and friends working and studying in more advanced countries. Moreover, greater pressure develops in a country to reform in order to attract more of their students and others back from abroad. All these reasons might explain why studies show that countries that send more students abroad experience more rapid rates of economic growth.
Some worried about immigrants bringing in diseases in this interconnected world with possible pandemics. I agree they have to be cleared medically, but that is no more a problem for immigrants than persons who enter the US on tourist visas, or Americans who return abroad after visiting countries where the disease burden is high. And certainly we can control the health of skilled immigrants better than the health of the mainly unskilled workers who enter the country illegally.