In A Right to Migrate?, Nathan Smith looks at the pretense that we are “defending our borders”:
But a counter-terror borders policy would look totally different from what we now have. For a start, we would probably permit the unrestricted entry of passport-carrying nationals of Mexico, which is not a terrorist source, and then cooperate with the Mexican government to prevent fraud, and thus prevent a flood of job-seeking migrants from camouflaging terrorist infiltrators. At present, there is not even a pretense that counter-terror is the major motivation for our border controls. The main challenge for applicants for US visas is to prove, not that they have no ties to terror, but that they don’t intend to stay and work.
The Left makes its own paternalist case for border controls:
The reaction of a leftist like Krugman to immigration represents a change in, or possibly an unmasking of, the motivation behind the welfare state. A generous view of the welfare state is that it is meant to serve the ends of mercy — a desire to alleviate the suffering of others — and/or social justice — a belief that poverty is (in part) a result of misfortune or exploitation, and therefore that we make life fairer if we tax the well-off to help the poor. But there is nothing just about guaranteeing a decent life to all who live north of the Rio Grande by closing the door of opportunity to those born further south. Nor is there anything merciful about denying a destitute Mexican the chance, however uncertain, of improving his lot in the United States. Krugman entitles his article “We’ve got a moral duty,” but in fact he has detached the welfare state from its notional moral content, and the “basic decency” he mentions is really a form of squeamishness: We know there is poverty in the world, we can’t alleviate it; we just don’t want to see it here.