My visceral reaction to arguments for less-than-100% open borders is to scream, and call names, and punch in the face. I will not act on these urges. I cannot punch 6 billion people in the face. Many of the people who oppose open borders are my friends; I like them. And intellectually I know that people do the best they can—they do not intentionally hold wrong moral beliefs. Instead, I write, and hope to persuade.

Let me offer an analogy. At the height of, say, the British aristocracy, one’s rights and privileges were determined by the social position of one’s family at birth. Almost all modern commentators will concede that this was deeply wrong. Whatever the barriers to achievement are in our current age, everyone seems to agree that at least the coercive ones should have nothing to do with one’s starting social position.

Today, around the world, one’s rights and privileges are determined by the physical position of one’s family at birth. It is not only the case that there are, in practice, disparities in the opportunities available to people born in different parts of the world; we have raised additional, coercive barriers to achievement that bind especially for those with unfortunate starting physical positions.

It is perhaps unsurprising that those who think they benefit from the current system wish to keep it. They trot out all kinds of practical-sounding excuses for why we cannot completely open the border. All of these reasons have analogs in the system of class-based privilege. Most of us, I imagine, would like to think that if we were aristocrats of centuries past, we would see through the lameness of the arguments for using the state to keep down the lower classes. Yet the widespread opposition to open borders today shows that we are not that good.

Go ahead. Spend some time with the analogy; wrestle with it. Tell me, if you can, where it breaks down. While I await your reply, I will tentatively postulate that there is no morally important sense in which it does. If there is such a thing as moral progress, then history will judge current opponents of open borders just as harshly as those who in the past made excuses for state-sanctioned aristocracy.

Radicals and especially libertarians are often accused, with some justification, of alienating their more-moderate allies. Perhaps that is what I have done today. A number of writers I admire have pointed to the case of Jose Antonio Vargas as indicative of what is wrong with the American immigration system. Vargas is admirable, but he will have little difficulty remaining in the United States. I am far more concerned for the hundreds of millions of potential immigrants, the huddled masses, who will never win a Pulitzer Prize. Must we, the new aristocrats, continue to oppress them?