This is from Gary North in the Journal of Libertarian Studies: The Sanctuary Society and its Enemies
In the United States today, the waiting period for citizenship is as short as five years. The waiting period is similar in other democratic nations. This, not the threat of economic competition, is the problem of immigration for the free society. Because the citizen authoritatively declares the law and seeks to impose it on others, he can become a threat to the free society. The problem is the moral content of his confession of faith and his possession of civil sanctions, not his productivity and his possession of economic sanctions. Mises was short-sighted here: a nineteenth-century, anti-clerical, would-be value-free analyst, i.e., a liberal. It is not the welfare state as such that creates the problem of immigration; rather, it is the confession of faith of the would-be immigrants. If their confession inherently threatens the moral and judicial foundations of the free society, then immigration is a problem, with or without the presence today of a welfare state. Freedom is based on more than private contracts. It is based on a moral vision, which includes a vision of the moral boundaries of the state.
This is the single most important issue of our time. Read it all.