Just read a sentence on The Daily Dish that contained a use of "on" that I find odd:
"Steve Clemons infers on who the Chinese would vote for:"
To me, the verb infer does not use any preposition to mark its object. So, I would say "X infers Y", not "X infers on Y". My guess is that Sullivan was trying to evoke the semantics of speculates on and transferred the syntax to infer. Just a guess.
[pssst, btw, I used to be able to cut-and-past from Word into Blogger to get formatted text like colors and highlighting (the quote above was green and shaded), but now I get an error because of all the crud code that Word includes. The crud code has always been there and Blogger used to handle it, now it don't. Is this part of Google's war on Microsoft?]