I have a couple of theories on this. First is the election cycle. In my theory the election cycle causes economic slowdowns through self fulfilling prophecy. Polititions on both sides of the aisle berate how the other side is going to hurt us financially. When that happens americans pull closed the purse strings.
Second, we have as a country and individually borrowed ourselves into oblivion. At some point we must pay the piper. Whether or not you agree with the recent wars on terror, we have spent alot of borrowed money to finance it. We spend money as though there is an endless supply. There is not. It comes from the pockets of hard working Americans. Our leaders would do well to remember that.
So, other than end the war, how will our democratic candidates fix our economy. Through healthcare, through allowing more immigrants into the system, through government subsidies on stem cell research, and research into alternative energy sources. All I have heard are options that cost money.
On the other hand I'm not sure McCain has a sure fire solution to the economic situation either. The one thing I know is that spending money in the form of loans to the Chinese that our children must repay is not the answer.