Above all else, the leading argument for Rob Portman for vice-president (besides the governing thing, which is a bit overrated in the heat of an election*) is that he hails from one of the most important regions (Hamilton County) of the most important state (Ohio).
That explains why this new poll from the Tarrange Group is so huge.
Time's Mark Halperin:
The poll suggests that Portman has a higher name ID in the state, and higher favorability, than the recent narrative has indicated.
He’s hugely popular in his home base of Cincinnati, but has favorability ratings that top his unfavorable numbers in Democratic-friendly areas such as Toledo and Cleveland, as well as among women statewide.
I posted a big, fat Ohio battleground guide yesterday, and one of the key points is that Obama turned Cincinnati's red Hamilton County blue by 5% in 2008. How troubling for the GOP is that? Even Bob Dole won Hamilton.
The big question is whether home-county boy Portman could reverse that. If so, he might be worth it for Romney. If not, then the idea of picking a Veep on geographic grounds takes a further hit for future generations.
(*Sure, Dick Cheney had the governing thing going for him, but he also helped address Bush's foreign policy deficit in 2000, so his selection had electoral politics, first and foremost, behind it).