A poll was conducted the two days following the Palin announcement that should give us some faith in the voters. Gallup seems to breeze over the fact that this poll was conducted post VP announcement and focuses more on the impact of the convention. However, I believe the results should still be comforting to Obama supporters. After the convention and the announcement of Palin, the percentage of Clinton supporters who said they were certain to vote for McCain went down by 4 percent and the number of Clinton supporters who said they were certain to vote for Obama went up by 18 percent.
http://www.gallup.com/poll/109957/Obama-Gains-Among-Former-Clinton-Supporters.aspx
I think this shows that when people really examine their beliefs, they realize that voting to make a statement is a mistake when it will come back to haunt them in the form of policy those voters do not support.