Fmr. Deputy Asst. Secy. of Defense: 'We're safer today, especially with Osama bin Laden silenced, but we're not safe '

What's the next front in fighting terrorism around the world? Where does our focus shift now? How can we effectively work with Pakistan after Bin Laden was discovered there and not in Pakistan? Will it sour U.S.-Pakistani ties? New information gathered from Osama bin Laden's compound show that just months ago Al Qaeda was planning "aspirational" attacks on rail lines to coincide with ten year anniversary of 9-11. Should we work in Pakistan in light of Osama bin Laden's death? CNN’s Kiran Chetry speaks to Peter Brookes, former deputy assistant secretary of Defense and senior fellow at the Heritage Foundation, about Pakistan and future Al Qaeda terror plots on the United States.