Here's an argument that they do, and that this helps explain why they aren't doing worse than they could have:
As bad a night as Democrats are going to have, it could have been much worse. Heck, it still might be much worse. We don't really know yet. For a while, I've been trying to get final data on the Democratic National Committee's persuasion and targeting efforts to see just how many seats Democrats could have lost without the help of a strong part, a party that is, in essence, an organizational reformation of an historic presidential campaign. Republicans do NOT have a strong party structure. The bulk of targeting efforts in several states is being conducted by outside groups.
The DNC's Organizing For America arm was never able to mobilize enough voters to match the relentless pulse of Republican enthusiasm, but it turns out that, in the past six months, they did a heck of a lot. President Obama's recent engagement with the election is one reason why Democratic enthusiasm has increased, but without the party to harness it, it would likely have dissipated. Make no mistake: if Democrats win Senate races in Pennsylvania, Colorado, and Nevada, the party gets some credit.
It's a plausible argument. Republican success has been driven by the Tea Party movement and other organizations outside the party structure. The Republican National Committee has had its work done for it by other groups.
