Book Review| Tides of Fortune: The Rise and Decline of Great Militaries

How and why do great powers change their policy regarding preparation for war, and when do they do so? Existing structural responses to the question of defence policy can be traced to the polarisation of capabilities, geography, and technology, as well as to cultural and domestic explanations, which focus on bureaucratic competition, service interests and strategic culture. These narratives are effective at giving the reasons for a particular state’s military posture, but less convincing about why states end up changing it.

Zack Cooper, who served in the US Department of Defence and the White House National Security Council, has authored an important book to address these issues. Tides of Fortune: The Rise and Decline of Great Militaries offers one interpretation, not about power as such, but about how leaders interpret their country’s relative power. It is that perception that accounts for the direction and timing of change in the militaries of great powers.

The argument is well-structured and concise. Leaders make two judgements: their state’s power relative to its rivals and whether it is getting stronger or weaker. These combine to give four possible stages. Defence policy is subdivided into objectives, strategies and investments, each of which generates a unique mix in each stage. A state which thinks it is going up increases its goals, embraces strategies of attack to control contested territories, and commits resources to platforms with long-term value. A state that feels it has reached its peak focuses on centralising its commitments and moving toward more defensive and less mobile forces. A state that thinks it is going down is turning to denial: it looks for ways to make its rivals’ aggression expensive rather than to command the field, and the more it does so, the more low-cost pawns it will use. The framework is laid out as testable hypotheses, and the book’s conception of its puzzle as a modern conundrum, namely why China, having followed a strategy that was working, abandoned it for one more open to new technologies, provides it with a narrative purpose.

There are six cases, spanning the period from 1890 to 2000. Cooper pairs maritime and continental powers in the same power phase so that the combination of geography and culture is changed, yet conceptions of power are kept the same. The two countries of the first pair, one an island, one a land power, with leaders sure of the strength of their nations in the mid-1890s, embarked on analogous programmes: sea control for the US and a battle fleet for Wilhelmine Germany. That convergence is hard to square with geographies or strategic cultures as explanations. By contrast, Britain and post-1918 France exemplify defensive shifts by states that feel their primacy is threatened, as do Japan’s failures during the Pacific War and Russia’s retrenchment following 1991. The logic of decline plays out most starkly in Britain and post-1918 France, and above all in Japan, where the turn to area denial and kamikaze tactics are the most extreme expressions of a state’s need to rely on its ultimate assets, and in Russia, where reliance on nuclear weapons is an extreme case of a state that can no longer project conventional force. The change in Britain was triggered by shocks around 1904 that convinced leaders that Germany was making progress, and similarly, until the late 1990s Russia did not feel the need to reform except when a serious external danger emerged. In all of these environments, the common theme is that military reform happens not when indicators change, but when leaders think they have changed, and that, as a result, sometimes the changes come later than the numbers suggest. This focus on timing is the most significant scholarly contribution in the book. It brings together two streams of scholarship that seldom interact: the international relations literature of power transitions and the rise and fall of great powers, focused on long-run change in material capability, and the strategic studies scholarship on military doctrine and innovation, centred on questions about organisations, technology and civil-military relations. Between these levels Cooper introduces a mechanism linking structural change to the decisions about fleet, force structure and procurement, by positioning leaders’ perceptions at the centre. The comparative design is well constructed, the case stories are neither superficial nor lacking in content, and the breakdown of defence policy into objectives, strategies and investments provides a common vocabulary and allows a true comparison.

The book is also prescriptive. Carrying the theory to the Sino-American rivalry, Cooper offers an analysis of the military reforms China has implemented to better reflect their new perceptions of relative power and to predict how Beijing’s defence policies will evolve. He makes a stronger argument for the United States: in its relative position, and given the trends of technology that favour defence and denial, Washington should focus on consolidating its objectives, adopting defensive policies and investing in less mobile forces, while pressing for reform to balance the military equation in Asia. It is a candid argument and comes in the middle of a broader rethinking of American defence strategy.

The book nevertheless leaves some questions unanswered, at least partly, due to the brevity of its case studies. Perceptions are hard to observe, and they diverge between civilian leaders in each state, between army and navy commanders, and between finance officials; in short, the leaders often differ in their perception of what is strong and weak. Perceptions too are influenced by the material indicators, alliances and domestic pressures that the theory aims to transcend, making it difficult to isolate their independent influence. Cooper concedes “threats” and “institutional resistance” “modulate” the timing and size of change, but in several instances these modifiers are more significant than he allows. There is also an unstated leap from description to prescription: History suggests that declining powers tend to consolidate, but it does not prove that the US should, nor does it resolve whether Washington’s leaders actually have the sense of relative decline that underlies the recommendation. Last, speculation on how Beijing saw itself is inevitably less certain than speculation based on well documented archives.

The framework has fertile ground for extension for readers and students of South Asia. India’s decisions to modernise its military, expand its navy’s reach to the Indian Ocean and discuss its force restructuring can be interpreted as those of a nation whose leaders feel they are slowly emerging as a major power, whereas the Pakistani dependence on the nuclear option and asymmetric strategies can be seen as a response to their country’s relative weakness. It remains to be seen whether a theory that rests upon the experience of the great powers will make its way to the regional and middle-power levels.

Tides of Fortune is an excellent, rigorous and timely book on military strategy and the great powers. It succeeds in demonstrating that perception is a missing link between structural change and military choice and that the time of change is as indicative as its substance. It will be useful to anyone interested in security studies and international relations, in military history, and in how states adjust their forces to changing realities, especially in view of the growing rivalry between Washington and Beijing.

Disclaimer: Views expressed are of the author(s) and do not necessarily reflect the views of The Statecraft Institute.