Your phrasing seems to be implying that Game Theory is a school of thought, as oppose to a branch of mathematics (one has adherents, the other doesn't). You also seem to be assuming a very limited frame of reference ("our national policy," "foreign governments") for an international field. Might you be confusing "Game Theory as a field is not designed as a predictive model for individual actions" with "certain governments believed Game Theory was something it wasn't?"