trust can never be separated from the condition of uncertainty, so rather than seek
toabolish uncertainty, the challenge is to open up space for trust-building under
uncertainty, and it will be argued that such space is potentially available in many
situations. A key contribution here has been the theory and practice of security
communities, and I argue that a promising example of the possibilities of nuclear
trust-building was the security community that developed between Argentina and
Brazil in the 1980s. The episode reveals the promise of trust in replacing nuclear
threats by a new international politics in which force is progressively delegitimated
as an instrument of state policy. Having explored the factors that promoted trust
between Buenos Aires and Brasilia, the chapter considers the lessons that can be
learned for nuclear trust-building elsewhere.
Anarchy, nuclear weapons, and the causes of war
Given the centrality that Waltz was later to accord nuclear weapons in the pre-
vention of war, it is noteworthy that he had not reached a similar conclusion in
Man, the State and War. Instead, the central thesis of his first classic book was that
‘war occurs because there is nothing to prevent it’^6 – not even the destructive
potential of nuclear weapons. Waltz provided a systematic framework for
understanding the causes of war which located explanations in three alternative
‘images’. The first focused on human nature. Waltz criticised Morgenthau and
Niebuhr’s human nature pessimism, considering that if human nature explains
war, it must also explain cooperation and peace. He was equally dismissive of
arguments claiming that humans are inherently peaceful and that war and conflict
are primarily the outcome of corrupting social structures. The second image
explains the causes of war in terms of the peaceful or warlike character of particular
states or particular types of regime. Waltz rejected this approach because he
considered that all types of states have gone to war. He argued that the first and
second images explain why particular wars occur (he called these the ‘efficient’
causes of war), but to understand war as a recurring phenomenon, we have to turn
to the third-image explanation of international anarchy which is the ‘permissive’
cause of all wars. Particular leaders might be peacefully inclined, and some gov-
ernments might be defensively oriented, but ‘No matter how good their inten-
tions’, Waltz argued, ‘policy makers must bear in mind the implications of the third
image.’^7 In the absence of a supreme authority to settle disputes between conflicting
sovereigns, the possibility always exists that states will resolve their differences by
force. Waltz did briefly consider whether the levels of destructiveness provided
by nuclear weapons changed this verdict.^8 His conclusion was that the atomic
bomb had no more revolutionised international politics than the advent of other
weapons that had been heralded in earlier times as the weapons to end all wars. He
cautioned in 1959 against any such nuclear optimism, believing that ‘The fear of
modern weapons, of the danger of destroying the civilizations of the world, is not
sufficient to establish the conditions of peace.’^9 He did not develop this reason-
ing further,^10 but the implication was clear: despite the arrival of increasingly
250 Beyond Waltz’s nuclear world