IN THE MALKIN Penthouse of Harvard's Kennedy School of Government, janitors worked in the fading light of afternoon to dismantle coffee urns and rearrange furniture. They also tried, gently, to disperse the crowd that had gathered around a 26-year-old academic wunderkind named Jesse Shapiro. Shapiro, who received his Ph.D. in economics from Harvard in 2005, is a fellow at the University of Chicago's Becker Center. He was wrapping up a brief triumphal tour of Cambridge with a one-day guest appearance. He could easily have used this custodial nudging to beg off any further discussion. Instead, he moved the freewheeling seminar that was dissecting his presentation--"What Drives News Media Slant?"--to a …