http://www.realclearpolitics.com/epolls/2012/president/us/general_election_romney_vs_obama-1171.html
Romney leads in six national polls, Obama leads in 3, and one is tied. I think it’s pretty safe to say that Romney leads nationally.
When you take into account the fact that all three polls where Obama leads have small sample sizes(under 1000), it becomes even more clear that Romney is winning the popular vote at this time.
Silver’s model is dependent on the swing state polls being more accurate or at least as accurate. If that proves to be wrong, then Silver’s model is going to need a bit of retooling for 2016.