Networks have not called the election but anyone with an internet connection and ability to use
the interactive maps, already knows that President Obama won re-election. Romney would have to sweep all of the swing states - which is impossible - because it looks like Ohio is going to Obama.
Below is a map showing that President Obama will still be re-elected even if Romney wins Florida, Virginia, Colorado, Nevada, etc ...
Therefore, there is no reason to have any doubt. Most likely the above map is completely wrong. The swing states will move to Obama - and
Nate Silver's 313 is probably correct.