Another addition has to be that this thread asks about theri CURRENT backhands. Throughout the recent years, Federer's backhand was far less consistent than it is right now, while Nadal's BH was a good deal more potent, than it is right now. Nadal beating Federer from the Monte Carlo final in 2008 to the Australian Open final 2009 has no bearing on how superior or inferior Nadal's backhand is to Federer's.
If Federer's forehand is the greatest of all time and Nadal's backhand, two-handed or not, is garbage, then Federer can pound it all day long and crush the inevitable short balls.
Federer CAN'T punish the inevitable short balls, because Federer would have to follow them to the net, where he is faced with what is possibly the best passing shot artist in history. Not to mention I never deemed Nadal's backhand garbage.