This is only so in a context. With a welfare state as the reality, we must restrict the movement of would-be parasites. That we have not, well.... the chickens are now home to roost and we are broke. The wealthiest nation the earth has probably ever seen is broke. Well done, ye psychotic progressive liberals!
In this sense, political philosophy is must like macroeconomics in that within a system, all players must act by the same rules or one group will live at the expense of another. Consider the example of China, economically speaking: "free trade" has NOTHING to do with free markets. China deliberately represses the natural growth of their labor market in terms of personal income. Any individual interfering with the interference earns their very own execution. We cannot have a free market trading system with China under these conditions because they are cheating and we are the ultimate losers in that game.
So it is with political situations. Wealthy USA has welfare that far outstrips anything the Mexicans might provide, so the parasites come here to latch on to the tit. Hard working Americans subsidize Paco Taco, parasite. This is clearly unacceptable, and therefore we must redefine the boundaries of the political system such that the environment is uniform in terms of the rules.
So, as you can see, simplistic answers are not... well... the answer. In a perfect world where all nations were "libertarian" and people were equally free, we would be able to have freely open borders... maybe. But the world is not so, and we must therefore control our borders in order not to be consumed by those who would eat us alive.
The question this all raises for me is this: what will the parasites do when all the hard working hosts are dead? Who will provide the basis of their parasitism thereafter? Will they work, or will they simply die? I suspect the latter. Therefore, since their destruction is a forgone conclusion, I see no reason we should go to our demise with them. Cut them off now. Let the rotten vestiges be killed off before they take the healthy organs with them.
