Mystery Pollster Mark Blumenthal is cautious:
It is true that some events produce a temporary "bounce" that rarely persists, especially if the coverage is uniformly good for one candidate and not so good for another (as seems to have been the case for the last few days). One possibility to consider is that surveys with short field periods might have some bias toward those who happened to be at home viewing that positive coverage.
Second, while Obama's lead on the Gallup was bigger than they have shown previously, it is only slightly bigger. Since Hillary Clinton endorsed him in early June, but before last week, Obama had led on the Gallup Daily by 7 points (once) and 6 percent (five times). And Gallup's data continues to show Obama doing very slightly better on weekends (but perhaps not significantly -- more on this issue later this week).
Third, and most important, if the volatility is about voter preferences and not poll methodology, it reflects the fact that (as David Moore has been reminding us) as many as a third of registered voters are willing to say they are less than certain about their choice. This hesitance is not unusual. Contrary to what Robert Novak implies in his column today, candidates rarely "close the deal" with uncertain voters in July, especially when they are non-incumbents and relative newcomers.
The Obama campaign is unconvincingly trying to lower expectations, with Obama even suggesting that the polls might tighten because he was overaseas. (Did his team neglect to show him McCain's national press clips?) Wait a week... and wait for a few national polls to come out.. and then make your conclusions.
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