How Leaders Assess Intentions Under Uncertainty: Costly Signaling, Leader Background Experiences, and Nuclear Diplomacy

How do leaders assess the intentions of their counterparts under uncertainty? This study
addresses this question by analyzing the development of nuclear programs. The technology
needed to build nuclear weapons and produce nuclear energy is indistinguishable. How,
then, can leaders identify a nuclear developer’s true intentions? An influential body of
literature suggests that costly signals play a key role in shaping states’ beliefs about whether a
developer of nuclear technology covets energy or bombs. I argue, however, that leader-centric
factors could also play a role in how states assess intentions. In particular, the background
experiences of leaders – particularly whether they are former rebels – might influence how
they are perceived. Leaders with rebel experience are generally seen as aggressive, revisionist,
and unreliable, making states more likely to conclude that their intentions are sinister. I test
the observable implications of these arguments for military conflict. The findings indicate
that former rebels who develop nuclear capacity are significantly more likely than their
non-rebel counterparts to be targeted in military disputes, suggesting that countries form
impressions about others’ intentions based on leader backgrounds. Costly signals, on the
other hand, do not seem to influence whether states believe that nuclear-capable states
covet bombs or energy. These findings carry implications for the role of costly signaling in
world politics and for leader-centric approaches to the study of IR.