The Tonight Show scored a 4.7 Nielsen rating on
Wednesday night, which if I'm doing my math right translates to
about 5.3 million households. (The Futon
Critic is the best place I know to find the Nielsen ratings,
but they only have the percentage-of-households ratings, not the
viewership data that Drudge quotes. For an apples-to-apples
comparison, TVNewser shows the debate reaching about 3.2
million households.) That's high for a non-Friday, about a million
more households than Leno drew on the nights before and after, but
presumably there's an overlap between the Fox News audience and the
people who tuned into Leno just to see Fred; Brit Hume mentioned
the Thompson appearance, after all. It's quite possible, even
likely, that Thompson reached fewer Republican primary voters than
the debate did, but of course there's no way to know for sure.