POLITICS: Samantha Power (where have we heard that name before?), a professor at Harvard’s John F. Kennedy School of Government, is in town Friday night to discuss her book, Chasing the Flame. It's about the 2003 death of UN High Commissioner Sergio Vieira de Mello in Iraq, and how we might better deal with the challenges of religious extremism, refugees, terrorism, and ethnic struggle. She also wrote a book on genocide, A Problem from......