What is the model-theoretic argument?

In a recent article, James Van Cleve joins a growing throng who have argued that Hilary Putnam's model-theoretic argument (and his "just more theory" response) begs the question against those who hold externalist theories of reference. Van Cleve has misinterpreted Putnam's argument. Putnam does not demand that the statements which make up the causal theory of reference must, themselves, do the reference-fixing. That would be question-begging. Rather, Putnam's argument is a "reductio", which can only be blocked with a theory of reference that is both substantive and plausible. Putnam argues that there is no interpretation of "causality" that meets both conditions.