The concepts that characterize post-Westphalian public health began to appear before SARS, but SARS still represents the first post-Westphalian pathogen for two reasons. First, the SARS outbreak was the first epidemic since HIV/AIDS to pose a truly global threat. Other new and not previously recognized microbes that emerged in the past 20 years had more limited capacity to threaten international public health because of inefficient human-to-human transmission or dependence on food or insects as vectors or on specific geographical conditions (WHO, 2003b). SARS posed a greater threat because of its more efficient person-to-person transmission and its fatality rate—comparable to some of history’s greatest infectious disease foes, smallpox and influenza.

Second, because of the nature of the SARS threat, the epidemic seriously challenged the emerging post-Westphalian governance system. SARS was a global public health emergency (WHO, 2003c), and the sternest measure of governance systems is their performance in times of crisis. The SARS outbreak provided the first opportunity to evaluate how the new governance approach for infectious diseases would fare under serious microbial attack on a global basis.

The Westphalian system is a system dominated by states (Scholte, 2001). The key principle of the Westphalian structure is sovereignty (Brownlie, 1998; Scholte, 2001). The sovereignty principle spins off corollary principles: (i) the principle of nonintervention (Jackson, 2001); and (ii) rules governing interactions among states arose from the states themselves and were not binding unless states consented to be bound (i.e., international law) (Brownlie, 1998; The SS Lotus, 1927). The combination of sovereignty, nonintervention, and consent-based international law meant that Westphalian governance was horizontal in nature, so that governance (i) involved only states; (ii) primarily addressed the mechanics of state interaction; and (iii) did not penetrate sovereignty to address how a government treated its people or ruled over its territory. The Westphalian system exhibited another characteristic—the great powers dominated Westphalian politics (Bull, 1977).

Infectious disease control became a diplomatic issue in the mid-19th century (Fidler, 1999). The regime that developed for international infectious disease control bore the imprint of all the characteristics of the Westphalian system. The International Health Regulations (IHR) (WHO, 1983), promulgated by WHO, illustrate the essence of Westphalian public health. The regulations are the only set of international legal rules binding on WHO members concerning infectious diseases (WHO, 2002), and they are are classically Westphalian in structure and content.

The IHR’s objective is to ensure maximum security against the international spread of disease with minimal interference with world traffic (WHO, 1983). The regulations seek to achieve maximum security against the international spread of