Isolationism is almost always talked about in the context of two wars: World War I and World War II. But it does intellectual injustice to the notion of non-involvement to use those as examples. The American economy was practically dependent exclusively on the shipments of war material to the Allies in World War I. (Not to mention that the US, by then with a pretty substantial sphere of influence in Latin America, was hardly interventionist: That's what the isolationists of the time, including some amazingly moral business leaders forming the Anti-Imperialist League, pointed out. Oh, if only business nowadays could approach those heights...) And in World War II, America backed the fascists then found all sorts of clandestine ways to assist the Allies when the fascists turned sour. After the war, they continued to back the fascists (though by then the Cold War was beginning in its infancy and thus America could hardly be considered isolationist anymore). That doesn't fit any definition of isolationism I can think of.
The same thing applies to appeasement, of course. Did America and the European powers really appease Nazi Germany because of fear or some other motive conservatives impute to them? Or was it simply because the victims of the Nazis weren't important enough to merit challenging the right of imperial states, not to mention someone who was very good at fighting off the Commies? Obviously the question is a difficult one to ascertain (there's probably elements of all of the theories involved, though of course I lean substantially to the latter hypothesis), but insofar as the answer was that the West simply could care less, "appeasement" is the wrong way of thinking.
This, of course, bears on Kelvin's point to some degree, but I think it illustrates a difficulty [Kelvin's initial article can be found here: http://blogs.zmag.org/node/3220#comment-62980]. Is the problem that the words "isolationism" and "appeasement" are inherently tainted? Maybe, but it doesn't seem so: While the exact definition may vary according to power preferences, the terms seem to be coherent enough. "Isolationism" pertains to the theory that America should be uninvolved insofar as possible with global affairs, while "appeasement" pertains to the attempt to "buy off" dictators with treaties and other means. What is the problem is the context: The mistaken belief that America is just too kind, too naive, and needs to buckle down and be prepared to deal harshly with the unwashed of the world who have yet to have reached our pinnacle of achievement and prosperity. Myths about World War I, II, American empire, the efficacy and justness of military force, etc. all are involved. But they don't bear on the language, though I guess Kelvin's point about "consumer tropes" would be fair enough: They bear on the context that the language is deployed in and the connotations of the words themselves and the context. That means that we have to go beyond deconstructing language. We have to present alternative contexts, alternative ways of thinking, which is a completely anti-postmodernist way of thinking. (Kelvin cites pomo, and while I don't think he matches with the priests of that bizarre little segment of academia, there has nonetheless been a bit too much of the bathwater taken).
Now, I tend to think the term "isolationism" in particular is just the wrong way of thinking about the problem. I think all nations' authority, including ours, should be subordinated in relevant areas and jurisdictions to a global system of governance, which is the first step in constructing a post-statist society that can be authentically free and equal. I think America has so much to do in context of this global arrangement to repair more than a century of privations and atrocities. I think that cultural exchanges, immigrations and emigrations, etc. are overwhelmingly positive. And so on. But I have to give some kudos to the Pat Buchanan type, or to the business and elite leaders so long ago, who seem to at least recognize that empire is wrong.
To put it succinctly: If the choice is between playing in our own sandbox and beating up other kids in theirs', the obvious choice, the only moral choice, is to confine oneself to the playground. It's up to Americans to determine if a third alternative is possible.