Thomas Friedman echoes my take on immigration here:
According to research by Vivek Wadhwa, a senior research associate at the Labor and Worklife Program at Harvard Law School, more than half of Silicon Valley start-ups were founded by immigrants over the last decade. These immigrant-founded tech companies employed 450,000 workers and had sales of $52 billion in 2005.
Being anti-immigration seems like another case of cutting your nose to spite your face--at the end of the day, you just hurt yourself. The benefits of legal immigration seem obvious in a supply-and-demand economy. Older, educated, and legal immigrants will usually be financial positives for several reasons: one, they are happy to be here, so they usually don't commit crimes; two, they're already educated, so the state doesn't have to subsidize their education or training; and three, being new residents, they cannot inherit anything or rely on family for income or assets; as a result, they must buy rent houses, cars, and other big ticket items, which helps the economy.
I've written about this issue before here.
Clark Winter agrees with Mr. Friedman and me. See here. So does Alan Greenspan. See here.