After adding fuel to the Munger-Drezner blogging feud (rather lopsidedly decided for Drezner, I might add), I’ve discovered more evidence to back up the rivalry: namely, that the latest US News rankings have Duke and the U of C tied for 8th place in the “political science” rankings. You’ll have to go and read the copy at your local bookstore to verify this yourself, unless you want to drop $14.95 for online access to the full list.
Of course, the standard caveats about the US News rankings being complete garbage apply. These rankings, based on refereed journal publications, are probably a bit better (and put Chicago well ahead of Duke), but omit effects such as book output, Ph.D. placement, and the like, as well as publications in journals outside of political science.