But I won’t go too far down that road, because even if there were evidence of causation (of governmental benefits causing immigration) and also evidence of material negative impact to the broader economy of such immigration - and the contrary has been shown to be true by numerous governmental and private studies, including general agreement among Nobel-winning economists - there is also the matter of values. Certain policies are not measured in terms of economic impact; we simply make things work when values dictate policy. For example, the medical profession will not abolish the Hippocratic Oath, no matter what the numbers. Similarly, abortion regulation will not be driven by economic arguments or evidence. Lunch counter sit-ins did not prevail because of economic logic or evidence.

The values at risk in the immigrant policy debate are for another thread, but they are sufficiently important that evidence alone cannot be enough to support a policy that contravenes our values. This is where the immigrant solidarity crowd comes from - it sees both the evidence and values on its side.

With that in mind, which immigration system allowed for easier legal entry into the U.S. - the one in place for Ellis Island, or the one we have now?

And would any of us want to live in a country in which emergency care and basic education were not freely available?

I also see no tension between libertarianism and opposing illegal immigration. There are two issues involved:

The first is, should the law be enforced, and should those who break the law be rewarded for doing so. I think the answer here, from a Libertarian/minarchist point of view, has to be yes it should be enforced, and no, lawbreakers should not be rewarded. Laws must be either enforced or repealed. They should not be ignored.

The second is, how many immigrants should be permitted. That is an economic and political argument with no right answer, especially in the context of a huge welfare state. I tend to believe that more immigration is warranted, but do not want it to be too fast. Unlimited immigration would cause workers to cross the border until the conditions of unskilled labor here were as bad as they are in Mexico, and it would take quite a while even for our freer economy to grow enough to restore things. We need to maintain a ratio of workers to capital that allows Americans to live well, and that means that population growth should not exceed capital formation. Unfortunately, there is no way to work out a mathematic solution to the problem, I have used math here as a metaphor.

That said, eventually I’d like to see open borders. It would have to be after the repeal of the welfare state, at least.