In her first debate against incumbent GOP Gov. Scott Walker, Democratic challenger Mary Burke alluded to her business background at least three times. In the second debate she made the reference about four times, and not covertly. "I'm a business person," Burke told the crowd and viewers at home. "I know how to make the tough decisions." That talking point has triggered a slight shift in campaign rhetoric, as a state Republican party that prides itself on a pro-business image is put in the unusual…