There are different schools of thought when it comes to choosing a Vice President. One can pick to reinforce a narrative ("this election is all about the economy"), or to balance the ticket (the nominee is strong on domestic issues but has little foreign policy experience, so pick a VP who is know to be an IR maven). One can pick based on electoral calculation or based on who is ready to take the reins of the presidency if disaster strikes. One can go for geographic diversity, or break barriers by selecting a woman or sexual minority.
But the selection of Rep. Paul Ryan (R-WI) as Mitt Romney's VP nominee has raised a new criteria -- effectively shifting blame for a loss. Already I'm seeing a bunch of different reports arguing over whether and how Ryan reallocates blame for a Republican defeat in November. Some say Ryan's presence on the ticket pins the loss on the far-right slash-and-burners that Ryan represents. Others vehemently disagree, saying this is still the "moderate" Mitt Romney's baby.
I'm not really sure what I believe. But I do know that if the first reaction to the VP pick by one's base is "how does this impact our upcoming November defeat", well, that's not exactly the sign of a healthy and confident campaign.