This.
Romney has yet to really start carpet bombing Obama with negative ads. Maybe those negative ads will spread blatant lies about Obama and his record but that strategy works.
How effective Romney's inevitable carpet bombing is and how the economy does from now till the election will determine most of it. If the Republicans get their way with the voter ID stuff (

voter fraud

) then that also swings this election in a lot of states. I don't see the debates really doing much. Both guys are intelligent and neither one is gonna catch the other with his pants down.