To begin, immigration is an extremely complicated issue with a variety of possible solutions. It’s also one of the areas where all libertarians don’t agree. There are a few main camps of thought though.
One group says that the state has no right to restrict freedom of movement, and that people from other countries should be just as free to move to this country as we are free to move within it. This is where Wendy McElroy comes down in this video. The libertarians following this argument tend to be more anarchistic in their reasoning. Some even contend that there should be no State to determine borders in the first place. Therefore immigration becomes a non-issue. It’s a minority, but a vocal one, that believe in this libertarian argument for completely open border immigration.
The second libertarian stance on immigration is more traditional and mainstream. These libertarians say that immigration is something that cannot be controlled by the free market, and the government has a right to check people as they come into a country. These libertarians might be in favor of unlimited legal immigration, as long as criminals are prevented from entering a country. This is where David Boaz stands, as well as John Stossel. They agree that the government should know who’s coming into a country when there are threats abroad. This is also where the majority of libertarians stand on immigration, and then they disagree on how much to limit immigration.
Some libertarians say that the government has a right restrict immigration even further than that because of the enormous welfare state that this country has. They don’t want to allow new immigrants into the country who may come to rely on the state. It’s a valid argument, and one that economist Milton Friedman has made in the past. These libertarians say they’d have no problem with immigration after the welfare state has been dismantled. A plurality of libertarians believe in this argument for immigration.
The problem with the last argument is that the idea that immigrants result in increased welfare spending doesn’t hold up to statistical evidence. According to multiple reports done by the CATO Institute, including this one, there is no causational tie between increased immigration, legal or illegal, and social spending. In fact, immigrants tend to pick states with less social spending because that means freer economies, and more jobs – which is why they’re really coming here in the first place.
Jeffrey Miron even contended that increased immigration would hasten an end of the welfare state instead of expanding it. He argued that since people are so universally opposed to immigrants receiving welfare, increased immigration would force that issue to a head, and welfare would be cut. It’s an interesting argument, and certainly a possible scenario.
As you can see from the video, and this article, where libertarians stand on immigration is not unified. There exists significant room for debate, and the issue isn’t likely to be solved any time soon.