Fallacy Nomination: The United Nations Fallacy

I like pie, gargling, the first of May, and naming fallacies. Today's fallacy nominee is “the United Nations Fallacy,” which is the error of assuming that supericially similar activities that take place inside two or more political jurisdictions may be usefully compared simply because those jurisdictions are each recognized as “nation states” by the United Nations. For instance, the United States of America has “an economy” and Liechtenstein has “an economy,” so let's compare them! Suppose tomorrow the state of Iowa and the city of Osaka are declared sovereign nations by the United Nations. Would it suddenly make good sense to compare their levels of birth defects, their GDP, their relative levels of “social capital”? If so, why don't we do it now? If not, why do we compare the U.S. to Liechtenstein, Mauritius, or Sweden?