Campaigning for the Senate in 2012, former Harvard law professor cum left-wing populist Elizabeth Warren touched down in North Carolina and told voters, “The game is rigged.” She was more right than she knew. As it turns out, North Carolina’s Democratic senator was doing some of the rigging. Now, Kay Hagan’s political future may depend on how voters react to the story. Hagan’s vote for the 2009 stimulus, coupled with revelations that the legislation resulted in taxpayer funding for her family’s businesses, has emerged as an October surprise in a race hitherto marked by her unexpected resilience in a difficult...