Simon Chesterman discusses his new book, "One Nation Under Surveillance: A New Social Contract to Defend Freedom Without Sacrificing Liberty". The discussion begins with a brief overview of the NSA and how it garnered the attention of Americans after 9/11. Chesterman discusses the agency’s powers and the problems the NSA encounters, including how to sort through large amounts of data. The discussion then turns to how these powers can become exceptions to constitutional protections, and how such exceptional circumstances can be accommodated.