Ayn Rand, known as one of the most effective and influential exponents of free market capitalism and individual freedom, viewed open borders and free immigration as obvious. Here is an excerpt from an interview of two students of Ayn Rand:

ARI: Can you give a specific example of when she responded angrily to a question?

MARY ANN: Someone asked her for her views on immigration, if she thought it was a good thing. And she got indignant immediately at the very idea that anyone might be opposed to immigration, that a country might not let immigrants in. One of the things she said in her answer was, “Where would I be today if America closed its doors to immigrants?” That really hit home; I’m sure everyone there realized that she would not have survived in Soviet Russia, that a person with her ideas would have died in prison, somewhere in Siberia. In her answer, she was defending people who were seeking freedom and a better life. And I think she was assuming that immigrants would be like she was—ready and able to make their own way, accepting help if voluntarily given by individuals but not expecting government handouts. But it was clear that she was angry at the idea, not at the person asking the question.

I heard people saying things like “I had no idea what I was really advocating.” Ayn was teaching the students the importance of analyzing their ideas, of understanding what was implicit in what they had been taught to believe and why it was wrong and often evil.

CHARLES: I’d like to add two points here. One is that her expressions of anger were the exception, not the rule. Two, they were often followed by applause from the audience—because the listeners were inspired by hearing someone speaking up for and defending what was right and good. They had heard, over and over again, mealy-mouthed speakers afraid to take a position—or suggesting that there are always two sides to a question —or that nothing is black and white. To have been subjected to those attitudes from childhood on up, and then to hear Ayn Rand take a firm position and defend it with conviction—this was a cause for cheering. The audience response was not only to the content of her ideas, but to her manner of expressing them. She was medicine for the soul.

MARY ANN: All those adults who taught us never to get angry, or if we did, not to express it, to hide our emotions when we were offended or felt we were being treated unjustly, to remain calm, to maintain an even keel, for God’s sake, don’t blow up, no matter what—these people didn’t do us any favors by urging us to suppress, to live like glazed, non-reacting creatures.

Also, many advocates of open borders have pointed to the fact that Ayn Rand herself was an “illegal immigrant” — see for instance this article in Reason Magazine.