In theory, one way Ryan could help Romney is by shoring up his GOP base. But Romney polls just as well or better among GOP voters in Wisconsin as Ryan. In a July poll by Marquette Law School, Romney was viewed favorably by 73% of Republican voters and unfavorably by 6%. Ryan was viewed favorably by 62% and unfavorably by 5%. In other words, Romney is doing just fine with the GOP base in Wisconsin. He wouldn’t appear to need Ryan to shore him up.
But the other way Ryan could help Romney is with independent voters. And the polls suggest he needs the help.
In the July Marquette poll, Romney was viewed favorably by 31% of independent voters and unfavorably by 40%. Ryan’s numbers were much better: he was viewed favorably by 40% and unfavorably by 25%. Public Policy Polling’s July survey showed a similar pattern.