Last week, the Obama campaign revealed a radio ad airing in Ohio that hits McCain on his and campaign chief Rick Davis' lobbying on behalf of a DHL that cost the state 8,200 jobs:

It was McCain who used his influence in the Senate to help foreign-owned DHL buy a U.S. company and gain control over the jobs that are now on the chopping block in Ohio.
This week, Obama's campaign turns to Wisconsin, going after McCain for his opposition to "buy american" rules that would require government agencies like the Secret Service to purchase its motorcycles from domestic manufacturers like Harley Davidson, a Milwaukee company.

Referencing McCain's recent visit to the Sturgis Motorcycle Rally, the ad goes right after McCain's supposed points of strength. From the text of the radio ad: