This chapter discusses how mass surveillance is increasingly used in liberal democracies in order to protect national security, but how such policies run up against the right to privacy. It shows that there is significant potential for state intrusion into privacy through mass surveillance of citizens’ digital communications, given the large extent to which people use digital communications and the detailed picture that this builds of their lives. To explore the rise of mass surveillance policies, and the privacy challenges that they raise, this chapter initially focuses on the USA as a case study. The USA is the global intelligence hegemon with vast spending on mass surveillance, but also has a strong constitutional commitment to privacy rights.

Examining this case study therefore provides important insights into the struggle between human freedoms, such as the right to privacy on the one hand, and security on the other hand. This struggle is illustrated in the concerns that Edward Snowden’s leaks in 2013 raised on oversight of intelligence agencies, and oversight of the telecommunications and social media platforms that form part of the wider “intelligence elite.” Widening the focus beyond the USA, this chapter observes two key problems with such mass surveillance policies and their inadequate oversight, namely: chilling effects and the drift to tyranny.