This will happen to whomever is Romney's pick. But Wisconsin Dems are frontline with Paul Ryan so they've been tasked with arming the missles with warheads. And given the time team Obama has had to study the short listers, the pick, as this piece points out, will come under immediate, intense fire. 

This is why establishment Republicans fear a Ryan pick. Pawlenty, Portman or anybody else will also come under withering attack, but it's feared Ryan is particularly target rich. I think he's the pick Romney needs to make. One can only hope Republicans are equally busy preparing to neutralize these attacks.