Realists are right about one thing, at least: by definition, great powers have more capacity to influence the behaviour of other states in the international system than do their less-powerful counterparts. Indeed, in the case of so-called ‘super-powers’ their actions can shape the system itself, even if that was not their intention. The surprisingly peaceful dissolution of the Soviet Union is the quintessential recent example of this possibility. Not only was this development entirely unexpected, not least by the Soviet leadership, but it had the effect of transforming the structure of the international order from bilateral to something else – although there is still some debate about what it actually is. What we can say with some confidence is that no one really saw this coming, not even the structural realists who, as the name suggests, focus intently on the principal ‘poles’ of the prevailing system. There are plainly limitations to an atomistic, Newtonian worldview when it comes to thinking about IR, even if it's not clear that any other perspective is likely to give a more accurate explanation of current, much less future, behaviour.

These initial observations are not intended as yet another argument for taking domestic politics seriously – although they are inevitably that, too, of course – but as an illustration of the limits to the conscious, goal-oriented power of even the most consequential of countries. They also illustrate how difficult it can be for policymakers and analysts everywhere to recognize underlying changes in key parts of any system, and the possible impact these may have. Because the Cold War balance of power looked so stable and such a fixture of the international order, change seemed almost literally unimaginable for many observers, including – perhaps especially – policy-making elites and security analysts in the Soviet Union and the US. As we saw in the previous chapter, the existence of the Blob at the heart of American policy-making has created a degree of intellectual inertia. Consequently, some observers persuasively argue that not much has changed in the way the world is viewed and the sorts of threats that are taken seriously: ‘the foreign policy establishment's very existence is a barrier to strategic adjustment’.