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.