One of the most dismissive terms thrown around in foreign policy circles is "isolationist." If you are an isolationist, you clearly have not considered the issues carefully and rationally, and need not be taken seriously. Libertarian leaning politicians such as Ron and Rand Paul are frequent targets of this epithet.
There may or may not be a handful of actual libertarians who are isolationist, but the reality is that libertarianism is among the most internationally minded philosophies. Examining several key areas of international relations makes this clear: International trade, diplomacy and the military, and institutions.
The most obvious place where libertarians are internationalists is economic relations. True libertarians advocate the free flow of trade and investment, without government restrictions. This is about as international as you can get. For libertarians, the origin of a product or service is irrelevant. People around the world should be able to buy and sell from each other without government interference.
Unfortunately, in most countries today, there is a strong sentiment for favoring domestic economic actors over foreign ones. This feeling manifests itself in various forms, such as tariffs and Buy National procurement policies. Libertarians stand almost completely united against this nationalist feeling, believing that trade and other economic interaction with foreign actors benefits us all.
Diplomacy and the military is a more complicated policy area, involving a number of instances of potential relations between domestic and foreign. Here, though, there is a strong case that libertarians are more internationalist than most others. Of course, in part this depends on what one means by internationalism.
Libertarians are most frequently accused of isolationism when they object to military intervention in foreign territories. That libertarians usually object to these interventions is not in doubt. However, use of the military cannot always credibly be called internationalist. Colonialism and conquest, although they do require contact with foreigners, are not generally a positive form of international relations.
More controversially, libertarians may sometimes object to peaceful aid to foreigners as well. But this is not done out of anti-foreigner sentiment. Rather it is based on skepticism over the effectiveness of aid and its misuse as a foreign policy tool, and a general preference for markets over government support. Libertarians certainly believe in private outreach among civil society groups in one nation to the people of other nations. The objection is only to the mismanagement of governments when they get involved.
Thus, for libertarians, war and government aid do not reflect true internationalism. To some extent, they are really about government bullying and condescension towards foreigners, the idea that we are superior to them and can use our power to re-make them in our image. In contrast, libertarians believe in treating citizens of other countries with respect and acting with humility.
Finally, there is the issue of international institutions. This is the area where libertarians are most likely to reject what is conventionally thought of as the internationalist position, as they worry about the power of these institutions. In reality, libertarians are not rejecting the idea of international institutions, but rather the specific policies pursued by some of these institutions. For example, if the IMF advocates Keynesian fiscal policy, and libertarians object, it is the policy they object to, not the institution itself. If there were international institutions that supported balanced budgets (or protected property rights), for example, libertarians would likely be supportive. There is no fundamental libertarian objection to international cooperation through institutions; the only concern is on specific issues of substance.
At a more conceptual level, the idea of limited government inherently pushes us away from nationalism and towards internationalism. As things stand now, most power is in the hands of national governments, who often use this power in ways that conflict with the interests of other governments. In other words, putting power in the hands of nation-states leads naturally to national conflict. By contrast, devolving power to local governments more closely connected with the people reduces the role of national governments and nationalism. It makes power more disbursed, and allows communities to connect with each other, regardless of the nation in which they are located.
Many commentators believe that libertarians are isolationist, anti-foreigner, and skeptical of anything in the international arena. However, the truth is that the internationalism of the establishment is often international in name only. We need to look carefully beneath the surface of what people actually advocate in the name of internationalism. Foreign-policy bullying -- as compared to simply letting others determine their own course -- might increase our contact with people of other nations, but it may do so in ways that lead to greater international conflict and reduced prosperity.
In the international arena, libertarians can and will have a strong voice and play an important role. That role should not be diminished by simplistic and inaccurate cries of isolationism.