This is a new ad that is running in Arizona. Some have suggested that this early expenditure is evidence that the DNC believes that Arizona will be a swing state next Fall. This is unlikely, unless they have mastered time travel and are referring to Arizona 2008
I think the DNC has a shorter term strategy in running these ads so early. The fact that the ad focuses solely on Romney indicates that the real goal is to undermine Romney's support in conservative States with early primaries in the hope that they can help the momentum of a breakaway Republican challenger coming out of Iowa. The DNC feels that Obama's best chance of winning in the Fall is against an untested conservative Republican nominee who is gaffe prone and inexperienced in running a national cmpaign. Given what little they have to work with, it is not an unreasonable strategy.