History shows that borders have always marked the limits of a political authority. Travellers seeking permission to enter have always been asked to respect that authority (when in Rome...).

In a world interconnected by technology and transport, how a state manages its borders affects a very wide range of interests, including public health, the environment, local identity, security, trade, tourism, and revenue.

How should governments manage the flows of people and goods across their borders? What powers are appropriate? Do thses powers differ from regulating similar flows of people and goods inside a country?

This monograph takes a first principles approach to these questions, as it explores the simple connection between state sovereignty and border management. The conclusions are relevant to many policy questions that are confronting New Zealand and other states, as they seek simultaneously to reduce and increase the barriers at their borders.