I find him to be a highly intelligent and intuitive person and a politician with the quickest learning curve we've seen in this generation.  I don't think he would have run this go around if he had not felt he could win this go around.  He may even have surmised that this truly is his best and only shot.  I take him at his word that he will not run again for President (unless it is as the incumbent President).  In fact, if he loses, I'd expect he'll run for Governor of Illinois and be quite happy in that position.

And I think he also rightly deduced that there is, indeed, "a fierce urgency of now."