McCain passes Obama in Gallup poll

So, what does it really mean that John McCain is now 4 points ahead among likely voters?

Probably not a lot. But, maybe something.

First, has enthusiasm for Obama changed the “likely voter” definition? What about the cell-phone issue with polling?

Maybe it shows nothing more than the volatility of voters this far in advance of election day.

Or maybe it shows that GOP social conservatives are starting to circle the wagons, even if not with much enthusiasm.