In this Manchester Union-Leader article Ron Paul argues that a non-interventionist foreign policy is not isolationism at all and explains why fairly well. Money quotes:
“A non-interventionist foreign policy is not an isolationist foreign policy. It is quite the opposite. Under a Paul administration, the United States would trade freely with any nation that seeks to engage with us. American citizens would be encouraged to visit other countries and interact with other peoples rather than be told by their own government that certain countries are off limits to them.”
“It is not we non-interventionists who are isolationsists. The real isolationists are those who impose sanctions and embargoes on countries and peoples across the globe because they disagree with the internal and foreign policies of their leaders. The real isolationists are those who choose to use force overseas to promote democracy, rather than seek change through diplomacy, engagement, and by setting a positive example.
“I do not believe that ideas have an expiration date, or that their value can be gauged by their novelty. The test for new and old is that of wisdom and experience, or as the editors wrote “historical reality,” which argues passionately now against the course of anti-Constitutional interventionism.
“A Paul administration would see Americans engaged overseas like never before, in business and cultural activities. But a Paul administration would never attempt to export democracy or other values at the barrel of a gun, as we have seen over and over again that this is a counterproductive approach that actually leads the United States to be resented and more isolated in the world.”