A Democratic candidate hasn't even been chosen but the battle for the Wisconsin governor's office already looks like it's going to be a tight one. According to a new poll from Marquette Law School, Milwaukee Mayor Tom Barrett is leading Gov. Scott Walker among registered voters 47 to 46 percent—a statistical dead heat. Similarly, among likely voters, Walker is ahead by 1 percent. Barrett's lead is much more secure in the Democratic primary—he's beating challenger Kathleen Falk 38 percent to 21 percent.