How and when can we justify the use of armed force by states? Humanitarian intervention is one possibility, much debated recently. The oldest justification of all, however, is self-defence. This is also hotly debated; the recent conflict in Iraq prompted the argument that the US-led operation was less an (acceptable) act of pre-emptive self-defence than an (unacceptable) act of preventive war. The idea that a state should defend itself against aggression seems intuitively reasonable and lies at the heart of the western just-war tradition and the principles of international law derived from it. By the self-defence of states, what we usually have in mind is an extrapolation to the collective level of the individual's right of self-defence. In Just and Unjust Wars , Michael Walzer, a leading advocate of the just-war tradition, describes this device as the "domestic analogy". War and Self-Defense seeks to break this connection. David Rodin argues brilliantly that individual self-defence cannot provide a morally coherent justification for "national-defense", and in the process offers a systematic rejection of the just-war tradition.
The first part of this important and imaginative study amounts to a forensic examination of individual self-defence. By what means is the defender granted the extraordinary right to take the life of the aggressor? Put another way, why does the attacker lose his right to life? Aggression might be a criminal act, for which its perpetrator loses certain rights.
The defender, on the other hand, is innocent and must be given special rights (to kill) to protect his innocence and thwart the crime. But this is to describe, rather than explain. For Rodin, individual self-defence - "a simple liberty to commit homicide in the defense of life" - must be constrained by the requirements of necessity, imminence and proportionality, and must be the product of a relationship between the holder of the right, the nature of the defensive act, the party against whom the right is held and the value to be protected or preserved. "A right of defense exists," says Rodin, "when a subject is at liberty to defend a certain good by performing an action which would otherwise be impermissible."
What then can be said of "national-defense"? How does the aggressor state lose its rights, and how does this forfeiture explain the loss of the right to life of an individual soldier on the aggressor's side? Here the domestic analogy unravels. The just-war tradition, argues Rodin, is weakened by an "inconsistent triad of propositions": soldiers on both sides who abide by the rules of war are morally innocent; yet enemy soldiers can be killed in war.
Rodin's elegant trashing of the just-war tradition will provoke a wide response. One riposte could be that in jus in bello the innocence of soldiers is largely beside the point, at least as far as complicity in the recourse to war is concerned. What matters is to establish standards of behaviour to make the conduct of war less barbaric. Another misgiving concerns Rodin's alternative to the just-war tradition. He offers international law enforcement as a philosophically coherent substitute, but acknowledges that this would entail "a moral transformation in the system of political relations itself". Something like a "minimal universal state" would be needed. Fat chance. In the end, those who insist that international politics and even warfare must be morally constrained will need some device to connect reality to morality. Which is why the just-war tradition still has legs.
Paul Cornish is director, Centre for Defence Studies, King's College London.
War and Self-Defense
Author - David Rodin
Publisher - Oxford University Press
Pages - 213
Price - £.50
ISBN - 0 19 925774 4