There's a curious pattern of reasoning one sometimes comes across (especially from the anti-Cosmopolitan Left) that one does better -- morally speaking -- to ignore destitute outsiders than to engage with them on mutually beneficial but unequal or potentially "exploitative" terms. In an old post on 'boycotting the needy' I discussed the cases of sweatshop labour and prostitution. I'm now thinking more about immigration and guest worker program.
It's a common concern, amongst people who are unwilling to offer citizenship to long-term migrant workers, that it would be an unjust society that relegates long-term migrants to a lower status of "second class (non-)citizens". Since we neither want to see ourselves as living in an unjust society, nor offer citizenship to these would-be immigrants, it's concluded that we must expel them from our borders instead! (See, e.g., Wellman's defence of limited-stay migration.)
There seems to me something extraordinarily perverse about this line of reasoning. It is to deprive the needy of a significant benefit (continued access to first-world labour markets) on the grounds that, if we allowed them this good, we would be subsequently obligated to help them more than we want to. So, for the sake of avoiding any such downstream obligations, we will harm them here and now. It's absurd!
Two aspects of absurdity jump out at me: (1) This sort of "moral reasoning" does not stem from any kind of good will or concern for others, but merely a narcissistic desire to oneself avoid any "moral stain". It is the epitome of fetishizing moral purity, at the expense of the actual things -- and people -- that matter morally.
(2) It turns a putative "right" -- to not be treated as a second-class citizen, unequal to the other members of society -- into a curse. This right is not to the benefit of would-be migrants, for our reluctance to respect this right causes us to do them an even greater harm, namely to expel them from our society altogether. But surely rights should not be curses. Rights are protections, given for our benefit, and so if a right turns out to be detrimental to our interests we must have the moral power to waive the right. But of course, if the right can be waived then there is no longer an objection here to allowing long-term migrant workers to remain within our borders where they've made their homes: one can simply make it a condition of their work visa that they waive the right to political equality.
That still seems pretty distasteful, I have to admit. And I think there's a decent case to be made that it wouldn't be permissible. But that just serves to bring out, I think, how much worse it is, morally speaking, to expel migrant workers or block them access to our labour markets in the first place. Perhaps we're morally obligated to grant long-term working visas and citizenship. But one thing is for sure: it can't be permissible to deny work visas on the grounds that one doesn't wish to subsequently be obliged to grant citizenship. That's just to double the harm, while pushing it out of sight so we don't have to face up to what we've done.
P.S. One might worry that we often don't want our rights to be alienable, because that would make us more vulnerable to exploitation. If you're at liberty to sell yourself into slavery, for example, then that's something that a would-be rescuer might demand before saving your life. Much better for you if you can't give up your right to basic liberty, so that it cannot be asked of you by those with power over you. But the obvious solution here is that we should only want our rights to be alienable when their presence leads others to permissibly abandon us. Such abandonment is often not permissible, which is why a would-be rescuer may not make exploitative demands before rescuing you from the desert island: if they're there, then they're obliged to rescue you regardless. Perhaps non-citizens are in a similar position, and we're obliged to grant them access to our labour markets, in which case their right to political equality is plausibly inalienable and we're obliged to eventually grant them citizenship in addition. But if it is permissible to "abandon" them and refuse them aid or entry, then I suggest they must have the moral liberty to give up the "right" to citizenship which is causing us to block their entry.