Ambers' take:
[T]hink of this development as simply a beachhead growing a few inches taller against a very powerful wave. Eight years of Republicans and President Bush. A Democratic advantage on the economy -- an economy which is not improving. A Democratic GOTV advantage. A Democratic enthusiasm advantage. A Democratic down-ballot advantage. And McCain was always, inevitably going to grow stronger as partisanship set in.
The polls will be worth looking at again a week after the GOP convention. All we know for sure right now is: it's close. The two candidates are both very formidable ones, big characters, with big bios, and differing appeals in a complicated time.