Although Jagdish Bhagwati's rhetoric is sometimes controversial, his notion that "Paul Krugman plays Michael Moore in the economics profession" is quite simple and well-spoken. After all, Krugman may well become the first person outside the field of literature to win both the Nobel and Pulitzer Prizes, the acme of achievement in BOTH academics and journalism.
Paul Krugman, now a new blogger and an Op-Ed columnist for NY Times, has largely contributed to the field of international trade theory, marcoeconomics and trade and geography. For a synopsis, see this. Quite informative for students in economics is his following words:
"It allowed models to replace metaphors as the basis for analysis. Without models, guesswork is all that we have to go on, and those who discipline their guesses with models are more reliable than those who fly by the seat of their pants, no matter how well tailored."
Here is another piece of review on Krugman by Harvard economist Edward Glaeser.