Harkins likened immigration to the importation of goods from Communist China. There is a case to be made for limiting trade which benefits totalitarian, threatening regimes. There is only so much wealth possible to society, there are only so many jobs to go around, goes this line of thinking. The reality of capitalism is quite different, fortunately. Wealth, created by new capital and technology, is limitless.
Full employment is possible regardless of how many people come into an area.
Granted, society often suffers unemployment, but this is invariably because of government interference in the economy through labor laws, minimum wage laws, licensing laws, and monetary regulation. I noted that, while libertarians generally do not support recreational drug use, we oppose the drug war. First, the drug war creates violent crime such as existed during the prohibition of alcohol. On the black market, potent drugs are easier to transport and few safety measures exist. Similarly, alcohol became more potent and dangerous during alcohol prohibition.