The excellent poll-watcher Charles Franklin of UW-Madison and now also of Polls and Votes, captures the action to date wordlessly. The graphic is based on his practice of averaging all of the credible national Repub preference polls and creating a trend line.
The previous sharp rise and fall of Bachmann, then Perry, then Cain seems almost humorous in retrospect. You’ll note that Bachmann’s spike didn’t get as high as the others (although hers was the first and the field was more crowded then). You should note that Gingrich’s rise is the steepest of all, has risen to the highest heights and, at least so far, hasn’t turned around.
Romney’s curve is the most complicated. It never goes above 25 percent (although Cain and Perry both broke through that level momentarily and now Gingrich has left 25 in the dust. Note that Romney’s curve twice tried to establish upward momentum but couldn’t sustain it. And — perhaps the biggest current worry for Team Romney — note that the current decline (he seems to be getting no benefit from Cain’s demise) is the steepest fall he has suffered. Until now, it seemed his challenge was to break through the ceiling of about 25 percent. But at the moment, his challenge is to avoid falling through the floor of 15.
Check out the full graphic on pollsandvotes.com.