Ron Paul has a short but sweet essay on the foreign policy wisdom of the Founding Fathers. Here's what Thomas Jefferson had to say in his First Inaugural Address (1801):
Peace, commerce, and honest friendship with all nations -- entangling alliances with none.
Two hundred years later, those words sound like something out of a dream, not a description of American principles. More and more, I'm coming to see a non-interventionist foreign policy as a key component of libertarian thinking, and the natural complement to the libertarian philosophy of voluntary, peaceful interaction among individuals.