Hear hear. When someone says “I understand comparative advantage, but in this case it doesn’t apply”, or “I understand comparative advantage but in this case it is overridden by other considerations”, my experience tells me that you can be nearly sure you’re talking to someone who does not in fact understand comparative advantage.
If I were permitted to write a licensing exam for economic commentators, I would surely incorporate a standard textbook exercise or two on this subject. Being lazy, I’d probably lift them from an existing textbook. For example:
Suppose that an acre of land in Iowa can yield either 50 bushels of wheat or 100 bushels of corn, while an acre of land in Oklahoma can yield either 20 bushels of wheat or 30 bushels of corn.
Which state has the comparative advantage in growing wheat? Which state has the comparative advantage in growing corn?
Suppose the residents of each state consume 200 bushels of wheat and 360 bushels of corn. If, instead of pursuing policies of self-sufficiency, each state specializes in its area of comparative advantage, how many acres of Iowa and Oklahoma farmland are freed up for other uses?
Anybody? Bueller? Grove?