Ryan's in-depth knowledge of budget numbers surely appeals to Romney. The strongest argument against a Ryan nomination is that a President Romney would need him championing his budget and entitlement plans in the House.
Another possible choice is Sen. Rob Portman, who campaigned all over Ohio with Romney. Like Romney, Portman comes from a family with Midwestern manufacturing management experience.
But he's also served in the House and as special trade representative and budget director. And he's had experience in presidential campaigns: He played Democratic nominees in debate prep for Dick Cheney in 2000 and 2004 and John McCain in 2008.
Two governors should make any short list, Mitch Daniels of Indiana and Bob McDonnell of Virginia. Daniels also served as budget director for Bush and is a crusader for entitlement reform. McDonnell has ties to the military as a longtime reservist and as the father of a daughter who served in Iraq.
All four of these potential vanilla running mates take conservative stands on cultural issues but are careful to show respect for those who differ. All have emphasized economics in their campaigns and have run especially well in affluent suburbs, as Romney has in Republican primaries.
Ryan wins big every year in Waukesha County west of Milwaukee. Portman ran well enough in suburbs to carry Ohio's three biggest metro areas in 2010.
Daniels won a higher percentage in Indiana's most affluent area, Hamilton County, than Ronald Reagan did in 1984. And in 2009, McDonnell carried Washington's Northern Virginia suburbs, where he grew up, though they had voted heavily for Obama the year before.
A double-vanilla ticket will be attacked as un-diverse by the media. But if the nominees have rapport and energy, as Clinton and Gore did in 1992, who cares?
The Clinton-Gore ticket regained Southern ground for Democrats. A double-vanilla ticket might enable Republicans to regain ground in affluent suburbs this year.