For example, Kerry beat Bush by over a million votes in NY, so closing the gap by another 300 thousand wouldn't flip NY from blue to red in '08.
On the other hand, Kerry beat Bush by less than 200 thousand in Michigan, so another 567 thousand net Republican votes puts Michigan in the red column in '08. A similar analysis shows NJ going from blue to red in '08.
The States Kerry put significant resources into, he did better in. But those states are few in number. He ignored the South and West and even half of the northeast. Without additional Media help, he would have been slaughtered across the board.