Here is Howard Dean ( via Slate ) making some points that all the Democratic candidates need to pick up on:

"When Ronald Reagan came into office, he cut taxes, we had big deficits, and we lost 2 million jobs. When Bill Clinton came into office, he raised taxes without a single Republican vote; we balanced the budget; we gained 6 and a half million jobs. George Bush has already lost 2 and a half million. I want a balanced budget because that's how you get jobs in this country is to balance the books. No Republican president has balanced the budget in 34 years. …You had better elect a Democrat, because the Republicans cannot handle money. … We're the party of responsibility, and they're not."

Here is a graphic illustration to help make that point more clear.
We now have a record $400 billion budget deficit and the job losses keep mounting every week.

Why would anyone want four more years of this?