Often, when a Libertarian expresses the sentiment that we should not be meddling in foreign affairs, they are automatically labed as an "isolationist". But such a label is miguided and ignorant of what isolationism actually is, and the term itself is often used as a buzz word to denounce anyone that dares to oppose a war or foreign intervention. The libertarian is a non-interventionist, not an isolationist.
Non-interventionism means peace, free trade, civil diplomacy and cultural exchange - without entangling alliances and enemies with other nations. The old Jeffersonian phrase is "Peace and trade with all nations, entangling alliances with none". This is a vital principle that was present at the founding of America. A non-interventionist strongly believes that the only justification for war is self-defense. They are therefore strongly opposed to militarism and empire/nation-building.
Isolationism, on the other hand, means wide-spread trade barriers, huge walls on the borders, no diplomacy and no cultural exchange. Many isolationists believe in having no foreign immigration at all. Wheras the non-interventionist would openly trade, the isolationist would put up tariffs and completely block trade with countries they do not like. Isolationists are protectionist. Whereas the non-interventionist would allow people to freely immigrate, most isolationists are quite hostile to the entire concept of immigration. The isolationist is hostile to a global free market, while the non-interventionist wants to protect the global economy.
Whereas the non-interventionist would support free cultural exchange, the isolationist is a seperatist and some of them are segregationists. Isolationists have a socially conservative impulse in them, although perhaps not as strong as other conservatives. The isolationist On the other hand, what binds isolationists and non-interventionists is opposition to war, although the reasoning is different for both and non-interventionists are often more consistant about it.
A non-interventionist simply is against war because it is mass-destruction of life and private property, and holds a "just war theory" in which war is only justified under limited grounds, of self-defense; of a defensive force. While some isolationists may take this view as well, many have their own alternative motives and reasoning for opposing war. Some separatist isolationists oppose war simply because they are against cultural contact, in other words for racist reasons. Some isolationists mingle with the religious right and are engaged in their absurd cultural warfare.
Non-interventionists are for pure neutrality in foreign relations, in which there are no official allies and enemies, in which sides are not chosen for foreign factional conflicts. Many isolationists, on the other hand, hold "beef" with certain groups and therefore are not truly neutral. The non-interventionist is quite likely to be sympathetic to the value of human life, regaurdless of race or religious creed. An isolationist would likely advocate cutting off all contact with China due to their fears about communism. While the non-interventionist may very well be completely opposed to communism, they would advocate cultural exchange and free trade with China.
A non-interventionist simply contends that foreign intervention into the internal affairs of other countries is full of unintended consequences and danger. They see a history of foreign intervention doing nothing but creating problems that are reacted to with more foreign intervention, in an endless cycle. And they see the invasion of liberty that takes place as the state grows at home and abroad. An isolationist does not have that ethical underpinning. Liberty is not their main motive. The non-interventionist's goals are peace and cooperation, while the isolationist's goals are seperation and no cooperation.
While Pat Buchannan was correct to come out against the Iraq War, and some of his reasoning was dead on, some of his reasoning was also arbitrary and not supported by an underlying dedication to liberty and peace. Isolationists and non-interventionists should not be mixed up and lumped together. One is a libertarian creed (non-intervention) while the other is a conservative creed (isolation). Thus, the word "isolationist" is constantly misapplied as a tool of stifling dissent to foreign policy. It is important for libertarians to make the distinction clear: we are NOT isolationists.