Nate's analysis is based on the conventional wisdom that a VP pick doesn't help outside their home state - although they can certainly hurt (Palin, Eagleton).
Another of Mr. Romney’s potential choices, Representative Paul Ryan of Wisconsin, drew more mixed reactions. Although Mr. Ryan should win his home district, pollsters who tested his numbers throughout Wisconsin found more tenuous results, with 38 percent of voters giving him a positive rating and 33 percent a negative one.How Romney's pick of a running mate could sway the outcome
Nate's projections on Ryan's help in Wisconsin:
Net impact on state popular vote: + 0.7
Additional state wins out of 50,000 simulated elections: 1,231
Additional state win percentage: +2.5%
State electoral votes: 10
Projected additional electoral votes: + 0.2.
So that's Romney's game changer. Add 0.2 EV in Wisconsin, and take heat across the nation for the Ryan budget - because as noted at the top of the diary, a VP pick can hurt.
Nate considered 14 candidates, and Ryan finished 10th in terms of helping to win the election.