The Gallup Daily tracker keeps offering surprises... I'll admit I did not expect the Hillary factor to be so large.
The Biden pick caused a dip rather than a bounce, though everyone likes Biden fine. Since there is a Biden bounce concealed in the numbers (+2-4), the countervailing Hillary-disappointment anti-bounce had to be in the mid-high single digits. The first day of all post VP-pick data is August 25, which was McCain's first lead in ages and Obama's lowest net in weeks.
Then the convention... first night of the convention was an improvement, but not much because the first of the three negative VP-pick days rolled off the average, so even without the convention the Obama one point lead is about what one would expect. In other words, the VP-disappointment factor was about equal to the convention positive of Michelle and Teddy and the good publicity of conventions in general.
Then comes Hillary night. The first report including Hillary night is Obama-48 McCain-42. Another VP-disappointment day rolled off, but the magnitude of the move suggest that polling the day after Hillary's speech had Obama well over 50% with a 15%-18% lead; almost certainly the best single day Obama ever had. The margin matches the Berlin high, but it's a violent one day move versus the slow steady build of the Europe trip, so the one-day sample has to be astonishing.
Then comes Bill Clinton and Joe Biden night. The last VP-disappointment day rolls off the average, Hillary day is still included and the entire sample is now conducted during the convention. So there is no way the rolling average wouldn't spike higher. But it didn't... only one point. That means the days polling for Bill and Joe was not particularly good. Sorry Big Dawg!
Tomorrow will include Obama's speech and has to be a big positive because it was a great speech and also well reviewed. That will be the only sample to include Hillary Day AND Obama Day and it will be a
MONSTER. The real head-scratcher will be Saturday.
Don't misread Saturday's Gallup as positive reaction to Palin! Any downward move Saturday versus Friday will be because the one day Hillary effect rolls off the average. Sunday will be the first day that says anything isolate-able about Palin.