The election is still two months away. People are just coming back from summer vacation. They will start to pay attention in early October. If the Republicans are leading in 8 seats currently held by Democrats now, it will only get worse for the Democrats (unless the Republicans REALLY screw up). Everything is going against Obama now.
Make no mistake, the GOP could very easily boot this. But even if they win, Obama will go into overdrive starting at midnight on 11/4 - I'm sure the GOP won't be prepared for it.