This article is based on a debate held on 22 March 2011 at Chatham House on ‘Was Iraq an unjust war?’

David Fisher argues that the war fully failed to meet any of the just war criteria. The war was undertaken to disarm Iraq of its WMD but the evidence that it had such weapons was inadequate. There were concerns about the justice of the cause, reinforced by doubts that those initiating military action avowedly on behalf of the UN had the requisite competent authority to do so, given the absence of any international consensus in favour of military action. The doubts were further reinforced by concern that action was being undertaken too soon and not as a last resort. Crucially, no adequate assessment was undertaken before military action was authorized to seek to ensure that the harm likely to result would not outweigh the good achieved. The individual failures mutually reinforced each other, so building up cumulatively to support the conclusion that the war was undertaken without sufficient just cause and without adequate planning how to achieve a just outcome following military action to impose regime change. It thus failed the two key tests that have to be met before a war can be justly undertaken, designed to ensure that military action is only initiated if more good than harm is likely to result.

By contrast, current coalition operations in Libya are, so far, just. This is a humanitarian operation undertaken to halt a humanitarian catastrophe that is taking place, with wide international support, including authorization by the UN Security Council.

Nigel Biggar argues that the fact that the invasion and occupation of Iraq suffered from grave errors, some of them morally culpable, does not yet establish its overall injustice. All wars are morally flawed, even just ones. Further, even if the invasion were illegal, that need not make it immoral. The authority of moral law trumps that of international law, and where the politics of the Security Council prevent the UN from enforcing the law, unauthorized enforcement could be morally justified. Further still, massive civilian casualties do not by themselves make an unjust war. The decisive considerations are those of just cause, last resort and right intention. Proportionality is not among them, because estimating it is far too uncertain. The persistently atrocious nature of the Saddam Hussein regime satisfies just cause; evidence of collapsing containment grounds last resort; and the Coalition's costly correction of early errors proved the seriousness of its good intentions. In sum the invasion and occupation of Iraq was, despite grave errors, justified.

Regarding Libya, Biggar notes the recurrence of conflict over the interpretation of international law. He wonders how those who distinguish sharply between protecting civilians and regime change imagine that dissident civilians are to be ‘kept’ safe while Qadhafi remains in power. Against those who clamour for a clear exit-strategy, he counsels agility, while urging sensitivity to the limits of our power. What was right to begin may become imprudent to continue.