The al-Qaeda attack on New York city on 9/11 was a stunning blow to America's security and intelligence apparatus. In the 14 years since, the US government has taken extraordinary measures to try to ensure that it could never happen again, but at what cost to fundamental values of liberty and human rights? Stephen Sackur is in New York to talk to Michael Hayden, who was the director of the National Security Agency on 9/11 and later director of the CIA. Did the US lose its moral compass in pursuit of the war on terror?