For anyone here favoring completely unrestricted immigration, I'd like to hear an integer: under open borders, how many of the Earth's 6.8 billion people would be living in America before we reach an equilibrium between immigration and emigration? I'd wager that, if the open-border policy somehow persisted despite all its consequences, our population wouldn't stabilize until we had about 1.5 billion living here.
Next question: is there no sense in which many or most economic refugees could be considered to be free-riding on our public goods and natural resources -- and charitable inclinations?
Bonus question: Can't a policy of consistently and publicly turning back economic refugees be seen as in the interest of potential economic refugees if 1) people-smuggling is sufficiently dangerous to those smuggled and 2) the target nation is ultimately going to foil the migratory ambitions of most of the economic refugees who attempt migration? In other words, if most are not going to get away with it, and it's dangerous, then can't it be good for them to be discouraged from trying it?
Jonathan, your words "chaos" and "feasible" completely paper over the disagreement you were trying to register when you said "there's nothing moral about impeding the free movement of people." My point is that the disagreement here really isn't about "morality" so much as it is about "chaos" and what's "feasible". But it's just not as much fun to couch disagreement in those terms, I guess.
My question about charity was thrown in only to make you think about the differential between the charity you'd extend to a beggar on your sidewalk compared to the charity you currently extend to, say, the most destitute people in Mexico. I was more interested in the angles about natural resources and public goods, but you ignored them (as is your right).
You also ignored my request that your answer contain at least one integer, and thus evades the point. If I thought open borders would net us only 50 million economic refugees, I might say what the hell, go for it. A billion is another story altogether. Magnitudes matter when it comes to free-riding. Given the plummeting costs of transportation technology, I don't think that costs would keep the number of refugees under hundreds of millions. Remember, with open borders, wealthy donors could completely and permanently change a refugee's life circumstances for as little as $100, simply by boating them to America and dumping them on our shores.
And, for the record, you ignored the bonus question, which pointed out a possible rebuttal to David Friedman's charge that Clinton is "a pretty poor excuse for a human being".
P.S. My question was about America opening its borders, not about all borders going away. If your "morality" complaint is only against America being a holdout as all other borders melt away, it loses all force in my judgment.
Regarding the EU, note that the concept of a "border" in these discussions is a demarcation between regions with different policies. I favor open borders between such regions, and note that opening such borders would not create a flow of economic refugees.