was first elaborated; it remains a theory with real vigour, with its adherents still keen
to improve it; it throws up big questions and offers important explanations; all
students continue to work in its shadow, whether they appreciate it or not; con-
ceptually, it draws attention to the power of structures (which in turn raises issues
about continuity at the international level); and its agenda items always play a role
whenever the curtain goes up on the international.
Though structural realism was field-changing after Theory of International Politics
appeared in 1979, in recent years the other main branch of realist theory (‘classical
realism’) has attracted more attention. Classical realism, a somewhat imprecise term,
is best understood not so much as a self-consciously unified tradition or school of
international political thought across 2500 years, but rather in relation to the ideas
of a self-defined, largely US-based, and IR-centric group whose main work was
done over a thirty-year period from the mid-1930s to the mid-1960s. This group
of IR classical realistssometimes drew on the supposedly timeless wisdom of statecraft
outlined by political theory giants of the distant past – Thucydides, Machiavelli,
Hobbes, Rousseau, and the rest – but it would be stretching things to herd all of
them into one self-conscious school across space and time. The most famous
theorists of IR classical realism were Hans J. Morgenthau, Reinhold Neibuhr,
George F. Kennan, John H. Herz, and Arnold Wolfers.^18 There were several non-
US affiliates, notably E.H. Carr in the UK. For most of them – and again Carr was
an exception – the primary causal factor in international politics is what is loosely
called ‘human nature’ (see Crawford’s chapter). Humans acting in the political world
are seen as driven by the vicissitudes of the human condition, the condition of
original sin, the sin of animus dominandi, and the demands of ‘homo homini lupus’.
Belief in the causality of such drives led classical realists to a picture of ‘politics among
nations’ (the title of Morgenthau’s most famous book) in which ‘evil’ lurked and
‘tragedy’ was invariably around history’s next corner.
For this group, Weltschmerz was the drumbeat of their lives and times. In
adulthood they witnessed the collapse of the old liberal order in the Great War and
Great Depression, two world wars within a generation, the rise of totalitarianism,
Auschwitz’s defiance of Enlightenment, and nuclear weapons strategising that
overturned Clausewitzian rationality about war. What is more, their witness to all
this followed childhoods shaped by liberal optimism and the largely war-free
nineteenth century. Not surprisingly, experiencing at first hand an era of converging
technological and ideological revolutions, these theorists were drawn to the darker
sides of human behaviour: they had seen the temptations and sometimes cata-
strophic consequences of political and technological power. They had also learned
about the limitations of power, and also of ethics. In these decades, IR classical
realists emerged, at their simplest, as exponents of an international political theory
of pessimism, legitimated by individual lives and turbulent times: at their most
radical, as will be seen, some of them sought to change what the rest believed to be
unchangeable.
Confronted by the world crisis of the mid-twentieth century, several of the giants
of classical realist thought offered radical visions of world politics that were
Realism redux 7