the source of the problem is beyond the jurisdiction and sovereignty of the state affected. Similarly, many countries, especially developing countries, need assistance from other states and international organizations in order to improve domestic public health. Mechanisms to facilitate international cooperation, such as international law, are crucial to public health responses to the consequences of globalization for infectious disease prevention and control.

This appendix examines how international law relates to the horizontal and vertical challenges for infectious disease policy created by globalization. International law forms part of governance response to globalization, which is explored in the first section. The second section looks at the development of horizontal international legal regimes relating to infectious diseases that developed in the first century of international health diplomacy, 1851–1951. The last 50 years have, however, witnessed changes in how international law relates to the governance challenges globalization creates for infectious disease policy; these changes are analyzed in the third section. The final section examines how current arguments connecting infectious diseases with foreign policy and national security concerns of the great powers might affect the role of international law in global infectious disease policy.

The challenges globalization presents for infectious disease policy demand governance responses. For the horizontal challenges posed by cross-border microbial traffic, the governance response centers on building interstate cooperation to minimize disease exportation and importation (see Figure B-1). The vertical challenges of inadequate public health systems inside states require strategies that seek to reduce the infectious disease prevalence within states through improvement of domestic public health performance (see Figure B-2). The construction of vertical and horizontal strategies on infectious diseases constitutes the fundamental objective of public health governance in the era of globalization, but as detailed in the next subsection, governance responses to globalization challenges come in three primary forms that ultimately are interdependent.

The state and its government constitute the key actor in public health governance for infectious diseases. Public health is a “public good,” the