For Wisconsin Governor Scott Walker, there's something awkward about the Harley-Davidson motorcycles that he has been posing on at presidential campaign stops: each one bears a sticker on its frame that reads "Union made in the USA." Walker has made the iconic American brand a centerpiece of his campaign kick-off tour this month, visiting four dealerships and sometimes showing off his own 2003 Harley Road King as he seeks to harness its appeal to older white male voters.