No borders, free movements of people. Adherents to that thought line are futuristic one worlders who do not believe in the concept of nationhood (Neither does Clinton or Strobe Talbot but they don't believe in liberty either). I have not seen official libertarian policy anywhere along that line. Some argue that there should be borders but people should be free to move about as they please. They also argue that a libertarian country would not be a welfare state and the mass amount of leaches we now suffer would then not be an issue. Valid point but the fact is we are a welfare state and the leaches vote democrat so supporting unregulated immagration is self defeating for libertarians and therefore illogical. There are libertarians who believe in nationhood and defense is one of the few legitimate functions of the Fed and secure borders is intregal to defense. These people also believe that a nation has the right to regulate who comes in and in what numbers. Being an American is not a basic human right ordained by God.
Trade: I am squishy on this one. Liberty means we should be free to do business with whom we please but "free trade" as delivered by the 2 parties is anything but that and seems to be more of a racket designed to benefit special interests. From a security standpoint if our national defense supplies are mostly made overseas we are not secure however if we didn't try to be run the world we would not have a need to be so worried. I like the concept of free trade with all and entangling alliances with none. Good will to all - and a strong defense. Early on our nation had no income tax and tariffs on imports made for a lot of the revenue. But all this is not now the case and who cares what I think.