From a New York Times article on where the campaigns are competing comes this.
Some campaign officials hope that Ms. Palin, an Alaskan, can broaden the ticket’s appeal in the Northwest, possibly gaining traction in states like Oregon and Washington, as well as shore up Mr. McCain’s standing with social conservatives who had, up to now, been lukewarm at best about his candidacy.
By this logic, Joe Biden should help to deliver Texas and South Carolina to Sen. Obama. Of course, he won't, and the idea that a hard-right social con like Palin would do anything to help McCain in blue territory like the northwest is the kind of stupid that passes for Republican strategy nowadays.
Let's go to the tape.
2004: 52-48 Kerry
Current Bush Approval: 32%
2004: 53-46 Kerry
Current Bush Approval: 30%
If she helps anywhere, Palin will help in red states like North Carolina, where McCain is now being forced to spend campaign money in defense because Obama is so close to him there. Now the New York Times could have easily fact checked this absurd assertion from Team McCain. They have the vast research resources of the NY Times whereas I only have The Google. And yet...
UPDATE: Meant to add this
By comparison Sen. McCain has a 3 point lead in North Carolina