Patri,
I overstated your position. My bad. On the other hand, you’re understating the position you expressed earlier when you gloss it by saying “If immigrants were more illiberal than residents, then my personal feelings about the costs and benefits of immigration would be different.” In the post above, you didn’t just talk about “the costs and benefits of immigration;” you talked about “how libertarians should feel about actual immigration laws in the real world.”
As I’m sure you know, establishing that unrestricted X is bad is not the same as establishing a case for a law aimed at prohibiting, minimizing, or controlling X. But when you say that “how libertarians should feel about actual immigration laws in the real world,” and then talking about “pragmatic tradeoffs” allegedly involved in one country ending up with a higher ratio of illiberal to liberal residents, or in using systematic government violence to stop that from happening, pretty clearly suggests that you think libertarians ought to at least feel more positively towards government force against would-be immigrants — e.g. violence to harass and restrain immigrants trying to cross the border, and/or violence to round up, confine, and then exile immigrants already within the U.S. who haven’t been officially approved by the government — even if, on balance, those more positive feelings are overridden by other considerations about the negative effects of the policy.
So, allow me to revise my position. Suppose it were discovered that native-born American children were, on average, more illiberal than Mexican immigrants. (This may or may not actually be true, for all I know.) Would you then think that this ought to affect how libertarians feel about proposals for mandatory sterilization laws, forced abortion laws, mass deportation of American infants to Mexico, or any number of other schemes that we might cook up to lower the ratio of illiberal to liberal residents in the United States? (Note that I am asking you how you’d feel about government laws to lower birthrates. Not just how you’d feel about lower birthrates happening somehow or another.)
Generally speaking, there are all kinds of statist methods of making one kind of people disappear from a stretch of territory, all of which you could go around evaluating for cost/benefit ratios. The question here is whether there is any policy so horrible that you wouldn’t even consider the necessary consequences of the policy a candidate for a “trade-off,” or anything that you would consider not yours to “trade,” even if the pay-off were right.
If there are any such, then it seems like you’re engaging in special pleading when you accuse Roberts of “taking the easy way out” by refusing to consider a coercive policy that he considers categorically unacceptable. Or if you’re not engaging in special pleading, it can only be because you think there is something special about Americans, or child-bearing, or American child-bearing, that allows you to refuse to consider population control laws that affect would-be American parents, but leaves the question of immigration laws open for consideration.
If, on the other hand, there is nothing (not even other people’s lives and livelihoods) that you would refuse to consider yours to trade off, and if there is no policy so monstrous that it wouldn’t be at least a potential candidate for achieving your demographic goals, then your position will, admittedly, be consistent. But consistency in ruthlessness is not something to take pride in.
My earlier remarks about the demands of justice also stand.