I am asking this before TMC, this way makes it more exciting.
Federer is fading quite fast, just like any other formal noumber 1. And many just could not climb back after the fall.The bigger question is not if Nadal can get #1, but can he finish YE #1? We all know about his late season fades, however if he gains enough points earlier through the NA masters series events, then he can repeat his late-season 2007 results and finish YE #1. Assuming Roger really declines.