Many Arizona conservatives would like nothing more than to see Sen. John McCain knocked off in a Republican primary. But few of them think Chris Simcox, the controversial founder of the Minuteman Civil Defense Corps who recently announced he would challenge McCain, is a serious threat to do it. Despite Simcox’s high-profile leadership on illegal immigration on the state’s southern border — a potent issue in the state’s Republican primary — party insiders say the 48-year-old former grade school teacher carries a heavy load of personal baggage and faces ample skepticism from rank-and-file Republican voters. “I’m very unhappy with Sen....