Both campaigns seemed to have decided that Hillary Clinton's 18 millions voters represent a key swing bloc in this election--both Barack Obama's speech and John McCain's pick were at least partially aimed at them. The fact that Palin is pro life and pro gun will be a block for many of Senator Clinton's supporters--but not all.
Palin will be seriously vetted. The Governorship of the State of Alaska is hardly the Presidency of the United States. She may demonstrate that on the trail and flub the debate against Joe Biden. It will certainly be harder for the McCain campaign to attack Senator Obama on the issue of experience.
But today, on first blush, it is a pick that helps McCain buttress the maverick image he intends to present and shakes up the race.