Forget globalization. Clear your mind of euphemisms like planetary ‘governance’. Drop the idea that the foreign policies of Western democracies are devoted to liberal goals, controlled by popular opinion or dedicated to peace. The inter-state system generates rivalry and war, today and tomorrow just as much as yesterday. Get ready for the great-power conflicts of the twenty-first century. Simply put, such is the scandalous message of The Tragedy of Great Power Politics.footnote¹ The book, however, is complex enough. Its author, John Mearsheimer, has for some time now been an iconoclastic voice in America’s complacent foreign-policy elite—one who, not by accident, has spent his career in scholarly work in universities, rather than serving as a functionary in the national-security bureaucracies whence conventional apologias for Washington’s role in the world are furnished. Not only is his writing refreshingly free from the cant that normally surrounds the world role of the United States, it is extraordinarily accessible: forceful, direct and clear, without a trace of the usual academic jargon. But it is also both erudite and sophisticated on complicated and disputed subjects within the field. Combining historical depth and theoretical vigour, it is likely—notwithstanding its heterodoxy—to have a wide readership round the world.

Intellectually, Mearsheimer is a product of the post-war tradition of neo-realist international-relations theory founded by Kenneth Waltz. The postulates of the neo-realist paradigm are economical, and stark. States, the principal agents of the international system, can be treated as so many black boxes or billiard balls, if our purpose is to analyse their inter-actions. Their differing domestic arrangements and pressures may be ignored. For the main lines of any state’s external policy are necessarily driven by the structure of the international system, whose anarchy—that is, lack of any consensual jurisdiction—forces states to struggle for supremacy over each other, in an endless search for their own security. A great power which fails to engage in a rational pursuit of hegemony will ultimately put its very survival at risk. This is the tragic fate evoked in Mearsheimer’s title.

But Mearsheimer breaks with Waltz in a number of crucial ways. First and foremost, he rejects the notion, developed by Waltz, that the logic of the international system tends towards an equilibrium, since all states must pursue the same aim of security, and any state that exceeds this goal, driving towards paramountcy over others, is bound to generate a coalition of its rivals against it. Aware of this inevitable backlash, great powers—in Waltz’s view—tend to become status-quo states, accepting balance-of-power constraints and acting defensively to uphold them. Mearsheimer’s key move is to reject this deduction of what he terms ‘defensive realism’. The imperative of survival, he argues, is incompatible with any equilibrium between states. For the only sure guarantee of survival, in an anarchic order, is primacy—that is, not balance with other powers, but predominance over them. The reasons are simple and two-fold. How can any power know what would be a ‘safe’ margin of advantage over its neighbours, one that would allow it to rest on its oars—and how could it predict the capabilities of its rival a decade or two into the future? These inherent uncertainties of the international order compel states, however powerful, to seek more power: there is no resting-place for them

Given the difficulty of determining how much power is enough for today and tomorrow, great powers recognize that the best way to ensure their security is to achieve hegemony now, thus eliminating any possibility of a challenge by another great power. Only a misguided state would pass up an opportunity to become hegemon in the system because it thought it already had sufficient power to survive.footnote²

In effect, what Mearsheimer does is project into the international arena the fundamental Hobbesian maxims: ‘Because the power of one man resisteth and hindereth the power of another: power is simply no more, but the excess of the power of one above that of another’—

so that in the first place I put for a generall inclination of all mankind, a perpetual and restless desire of Power after power, that ceaseath only in Death. And the cause of this, is not alwayes that a man hopes for a more intensive delight, than he has already attained to; or that he cannot be content with a moderate power; but because he cannot assure the power and means to live well, which he hath present, without the acquisition of more.footnote³

These are the relentlessly logical premises on which Mearsheimer, correcting Waltz, develops a doctrine of ‘offensive realism’. In this world, there is no such thing as a satisfied state. Far from behaving defensively, he argues, ‘a great power that has a marked power advantage over its rivals is likely to behave more aggressively because it has the capability as well as the incentive to do so’.footnote⁴