Do nations have a right to exclude?

The excellent philosophy bites podcast has an interview with philosopher Sarah Fine about whether or not a nation-state has a right to keep people out.

It's an interesting question in the abstract, but it seems essentially practical as the US and other nations struggle with immigration policy. Nations assert a right to determine who can enter the country, but what is the foundation for that "right"? Saying "it's always been that way" doesn't seem like a satisfactory answer; for a long time, slavery was "the way we've always done it."

In the interview, Dr. Fine confronts many possible arguments about it, and points out the problems those arguments have as a rational basis for such a right. Whether or not you agree with her, it's an excellent example of philosophical analysis and reasoning applied to an interesting question.