External Intervention and the Politics of State Formation is an exciting addition to the political science scholarship that brings together the sub-disciplines of comparative politics and international relations. As reflected in the title of its last chapter, this book demonstrates substantial intellectual efforts in “domesticating international relations” and “externalizing comparative politics.” The previous scholarship that integrates comparative politics and international relations, most prominently represented by Thomas J. Christensen's Useful Adversaries: Grand Strategy, Domestic Mobilization, and Sino-American Conflict, 1947–1958 (Princeton University Press, 1996), tends to trace the origins of states’ external behaviour back to domestic politics. However, Chong adopts an innovative perspective by building a logical connection from international relations to domestic politics rather than the other way around. By highlighting the importance of external actors, Chong argues that sovereign state formation in the fragile polities of the global periphery is often driven by sufficiently competitive foreign interventions from without rather than the rise of nationalism from within.

Chong's theoretical formulation is drawn from case study of state formation processes in China, the Dutch East Indies/Indonesia, and Siam/Thailand between 1893 and 1952. China is used as the primary case, with four chapters of detailed examination. The Dutch East Indies/Indonesia and Siam/Thailand are used as secondary supporting cases, with a single chapter each. Overall, the book successfully brings together the North-East Asian and South-East Asian historical experience through a coherent account of evolution from empire, colony and suzerainty over vassals to sovereign statehood under the fateful impact of foreign intervention. The author has conducted thorough archival work on the case of China in Beijing, Nanjing and Taipei. All three case studies reflect the author's impressive capacity to combine political science theories with historical methodology, as well as the possibility for future research that further strengthens the tie between the two disciplines. The year 1893 is chosen as the common starting point because it was just before the Sino-Japanese War of 1894–95, the launch of the Dutch Ethical Policy in the East Indies, and the beginning of a major series of modernizing government reforms in Siam under King Chulalongkorn. This study cuts off in the year of 1952 because it marks the conclusion of Second World War peace processes at the San Francisco Conference.

Chong argues that the year 1922 was a critical watershed during this time frame. He contends that throughout 1893 to 1922 political elites from Britain, the US, Japan, Russia/the Soviet Union, Germany and France had mixed perceptions about the opportunity cost of intervention in China, the Dutch East Indies/Indonesia and Siam/Thailand. However, the opportunity costs of intervention were perceived as uniformly high for intervening external powers between 1923 and 1952. The author suggests this fundamental shift stemmed from “the intensification of systemic competition after World War I” (p. 19). When expected opportunity costs for intervention were low, outside powers would seek to deny completely their rivals’ access to a fragile state. However, with high expectations of costs for intervention, major powers tended to settle on promoting non-privileged access to a fragile state, which was considered as the next best alternative to their greatest fear – territorial domination by adversaries. When all external powers share this view, foreign interveners, in collaboration with their indigenous partners, would help a fragile state establish greater centralization, territorial control and external autonomy – the three key criteria of sovereign statehood as Chong defines it (pp. 224–25).

At first, the argument that foreign intervention can bolster the development of sovereign statehood “under the right conditions” seems somewhat counter-intuitive because foreign involvement is commonly perceived as the origin of either domination or fragmentation in fragile polities (p. 224). Nevertheless, when examined more closely, this book boils down to the contention that foreign intervention will contribute to state formation only when all foreign powers regard the cost of intervention as high. The foreign powers will thus minimize their capability commitments in the target state, while “helping to put local actors in a position to independently manage and defend the polity” (p. 226). Despite his repeated emphasis on the importance of foreign intervention, Chong seems to be arguing instead that a systematic contraction of foreign intervention and a collective international recognition of the independence of local actors contribute to state formation. From this perspective, Chong probably refines rather than challenges the popular perception of extensive foreign intervention as impeding the development of a sovereign state. His thesis also echoes the common claim that rivalry among outside powers can provide opportunities for a weak polity to achieve independent sovereign statehood.

Chong's account is a powerful critique of the officially endorsed nationalist history that post-scribes nationalism to past events, although the book might not have done justice to the indigenous nationalists in the global periphery as it assigns them little agency. Chong challenges standard nationalist historical narratives, replacing the “black-and-white” division between outside actors and indigenous groups with a multi-dimensional image of relationship between the two sides. In his analysis of the conditions under which local and foreign actors cooperate to establish political order in a fragile polity, Chong daringly contends that the roles played by nationalist groups in the process of state-formation are much more passive than outside powers (p. 227). According to Chong, the fortunes of nationalist groups such as the Chinese Nationalists and Communists and the Indonesian Republicans were determined by the degree of external sponsorship (ibid.). Here Chong's argument might have gone to the extreme of depriving the local actors of the Third World their agency in state formation. One may question how economic, military and institutional resources from the Western and Japanese interveners were adopted and transformed for the purposes of state formation.

The book also opens up discussion on three pertinent issues. First, Chong consistently follows the realist tradition in political science and adopts a purely materialistic approach. Although this materialistic perspective can be persuasive in its own right, one wonders whether normative and ideational factors should be largely regarded as insignificant in a book that engages in the scholarly debate on nationalism. Second, the book adopts a broad definition of “foreign intervention” which has a wide spectrum from colonialism and gunboat diplomacy to current US nation building projects in Afghanistan and the international intervention in Egypt during the Arab Spring. Yet colonialism and foreign interventions in the post-Cold War era are of utterly distinctive nature and probably cannot be easily juxtaposed. Finally, although the author insists that the historical processes in China, the Dutch East Indies/Indonesia, Siam/Thailand are “by-and-large independent from each other in the periods of this study” (p. 18), the circulation of funds, technology and nationalist ideas between China and South-East Asia through the overseas Chinese network is a well-studied topic that is neglected here.

In sum, Chong has made an admirable effort to synthesize the sub-fields of international relations and comparative politics, as well as the larger disciplines of political science and history, through ingenious theoretical design and meticulous archival research. This book is an inspiring example for future works on the subject.