This election is about the fact that Republicans have made us less safe and that Congressional oversight is critical to ensure that Bush and company, with their tragically misguided decisions on Iraq and homeland security, don't make us even less secure over the two years they have left. Period. End of message.
There is, of course, a lot more to this election than the above but we really need to keep our focus on the biggest issue and not confuse the folks that in their insanity are thinking of voting Republican again. This is a good tight "elevator speech" and gets the most important point out there with little room for dispute.