A down and dirty campaign from "both sides"?

It isn't clear from Howard Fineman's discussion why the Republicans would want a "dirty" campaign. It is the Democrats who have nothing else to run one. Republicans have a lot to run on -- Obama's disastrous record and how they would do things differently. From Howard Fineman on Hardball:

"I don't think that the numbers are good enough, and I don't think that the temper of the country are going to be good enough, which is why when I talk to Democrats outside and inside the White House, as I did today. What I heard was a slightly different message. It's not going to be a 'Morning in America' campaign, it's going to be a darkness at midnight campaign about the Republicans. it's going to be about the fact that the Republicans in Congress pushed Paul Ryan's bill Medicare, about how they pushed Cut, Cap and Balance. It's about how Republicans wanted to dismantle Wall Street reform. It's going to be about how the Republican presidential candidates have embraced the Tea Party. Those are going to be the two central messages of a campaign that's mostly going to be about attack. I think this is -- just like 2008 was in some respects an uplifting campaign, from both sides, this one is going to be down and dirty from the beginning from both sides."