Gallup's latest numbers are bad for Obama:
Across all of the various debate-reaction polls Gallup has conducted, Romney's 52-point win is the largest Gallup has measured. The prior largest margin was 42 points for Bill Clinton over George H.W. Bush in the 1992 town hall debate.
Blumenthal, who provides the chart above, says the recent tightening isn't unusual:
The polls have seen the race shift from 1 or 2 percentage points in favor of Obama to a better than 4-point Obama lead, and now back again. These are relatively small shifts, theoretically involving the changing preferences of just one voter in 50 (though shifting enthusiasm, affecting which voters qualify as "likely voters" or otherwise choose to participate in polls, likely plays a role as well). Either way, this modest polling "volatility" is well within the precedent of recent elections and may well continue over the next four weeks.
Nate Silver's related thoughts:
If the polls settle in at showing something like a 1- or 2-point lead for Mr. Obama by this point next week, that would be reasonably well in line with where our model and others think that the election “should” be based on economic trends; it would no longer be as appropriate to think of Mr. Romney as being an underachieving candidate.
Nate Cohn wonders if Romney's bounce will fade:
The evolution of the post-debate tracking polls suggests that Romney’s post-debate bounce might be fleeting, or at least smaller than the polls conducted immediately after the debates.