Just like choosing him as VP was going to put Wisconsin in play.
The top of the ticket matters a lot more when it comes to the effect in an individual state.
It is worth noting that Romney did nearly seven points better in Wisconsin than McCain did.
Ryan's worse performance for his House seat was in 2012, the same time he was on the presidential ticket, so I don't think he's got much ability to win statewide.
It isn't surprising that when a politician's profile rises, partisans on the other side will have more reasons to vote against him.
