Do Polls Drive the Narrative, or Does the Narrative Drive the Narrative?

We're at the stage in election coverage where everything has now been said, but articles have to still keep being written by journalists.  Now there is an uptick in meta-campaign articles, not about how the media portrays horse-race campaign coverage, but about how the media portrays how the media portrays horse-race campaign coverage. 

The flagship article for this meta trend is this Alec MacGillis article from The New Republic. He argues that the media has been responsible for this illusion of the presidential race tightening because it provides a more compelling narrative, ignoring evidence that would indicate the race isn't actually that close.

Over at the Washington Post, Chris Cillizza tweeted after the debate: “Romney win in first debate still more meaningful for arc of race than Obama win in third debate.” And yes, if we declare it less meaningful for the “arc”—another word for story!—then of course it will be so. We liberal reporters do love our tautologies, even if we’re not always aware of them.

The problem with MacGillis's anti-narrative narrative is that there was actually a substantial and sustained drop in the polls that began roughly around the night of that first debate.  And I'm not talking about national tracking polls like Gallup's weird presidential tracker-of-fleeting-passions-of-likely-voters.  I mean a drop in the state polls, the only polls that matter.

This is a chart of the average margin in polls in the nine closest battleground states, as determined by my ongoing research into charting the median active credible poll in each state.  The nine battleground states are Florida, Virginia, North Carolina, New Hampshire, Ohio, Wisconsin, Iowa, Colorado and Nevada.  Positive values indicate an Obama lead, negative values indicate a Romney lead.

Obama crested around October 3rd, the night of the first debate, a time when most poll averages had Florida, Colorado and Virginia in the Obama column.  The numbers kept plummeting after the second debate, but may be leveling off now, though there has been no post-third-debate polling as of yet.

This isn't an artist's rendering of a media-driven campaign narrative.  Based on those polls, here's what the electoral college looks like:

Some have indicated that this Obama drop may have nothing at all to do with any debate or really any campaign event whatsoever, and that it merely represents conservatives finally rallying around their presidential candidate.  There are also liberal poll Unskewers who believe that the polling firms themselves, led by arch-conservative pollster Scott Rasmussen, are forging poll numbers in order to drive the numbers-based narrative pictured above. 

If this was the case, I would have expected the same trend to be present in the senate polls.  If conservatives are rallying around their presidential candidate, they should also be driving their senate to higher polling margins (after all, since the vast majority of senate polls are conducted at the same time as presidential polls, they're sampling the exact same people).  Or if there are poll-driven Republican narratives, the Rasmussens of the world should be able to drive the composition of the senate rightward too.  But this hasn't the case.

Here's the same chart as above, except with D-R senate margins.

Democrats are currently doing about the same as they were on October 3rd: kicking ass overall in the 14 closest races.  Because of the polls, the senate projections basically all look something like this:

Why the stark difference in polling "trajectory" (to use Alec MacGillis's favorite word) between the presidential contest and the senate contests ?  The most logical conclusion is a nationally televised debate that showed fickle center-right undecideds that Mitt Romney wasn't the scary/bumbling caricature they'd heard fleeting rumors about.