Emanuel's ferocity in a letter two years ago. He's dangerous, Cole told Fortune then. He has a closing intensity. When he's got a political kill in sight, he's absolutely relentless. But David Gergen, a CNN senior political analyst who has worked in five administrations, said the contrasting styles between Obama and Emanuel could help the new president get things done in Washington. They are obviously setting up a good cop/bad cop routine in the White House.... Barack Obama can be the good guy, Gergen said. iReport.com: Who should be in Obama's cabinet ? Emanuel has made a career of being the tough guy. In the 2006 Fortune profile, Begala described Emanuel's aggressive style as a cross between a hemorrhoid and a toothache. I love Rahm, but that's a small group of us, he told Fortune. CNN's Ted Barrett and Don Lemon contributed to this report.