Presidential candidates are a breed apart, often propelled by traits that have shaped their careers and have deep roots in personal histories. Often their greatest strength can turn at supernova speed into their greatest weakness. The exact qualities that set them apart from the field trip them up eventually over the long haul of a presidential campaign. New Jersey Gov. Chris Christie's big personality and bold political instincts have put him on the national radar. His willingness to speak from the gut has enabled him to connect directly with voters on both sides of the aisle better than any of the other candidates. But that same bluntness sometimes jeopardizes the very agenda he wants to accomplish. In this series of eBooks, The Washington Post is exploring in-depth all these key characteristics of the leading presidential contenders, the very characteristics that could help make one of them the country's next commander in chief—or forever sink their presidential ambitions.