Kieran McInerney

This thesis examines the Reasonable Probability of Success criterion of jus ad bellum. Chapter One provides an initial explication of this principle. It outlines its historical origins, and explains the rationale for requiring that this criterion is satisfied in order for it to be ethically permissible to wage war. Chapter Two offers some guidance for interpreting and applying the Reasonable Probability of Success criterion. Chapter Three denies the claim that this criterion is redundant because it can be subsumed by the Proportionality criterion. Chapter Four of this thesis denies the assertion that the Reasonable Probability of Success criterion violates a feasibility constraint. Chapter Five denies the claim that this criterion grants the United States a form of hegemonic moral immunity. Chapter Six of this thesis argues that the contemporary understanding of the Reasonable Probability of Success criterion conflicts with widespread intuitions towards historical instances of war. Chapter Seven of this thesis critically evaluates Statman’s so-called Honour Solution, presenting a series of problems with his proposal. Chapter Eight argues that the Reasonable Probability of Success criterion could actually have been satisfied in the historical cases that are seemingly troubling. It maintains that the contemporary understanding of the Reasonable Probability of Success criterion is mistaken, because it erroneously assumes that defence of others requires a state to mitigate or avert the imminent threat that it faces.