It would be interesting

...if the election goes in one of these ways.
Obama wins the electoral college but loses the popular vote. So Obama's last term is like Bush's first term.

or
This is not Obama's last election.
Imagine he loses by a close margin. Say Romney gets 50.1% and Obama gets 49.9% or it would be Romney 49.9% to Obama 49.8% with the remaining 0.3% going to third parties.

As a result there would be a call for Obama to run again in 2016