Was the United States right to invade Iraq in 2003? Are we right to fight there now? These are distinct questions, but the principles by which each must be answered are the same – the principles of the Just War Theory. This theory, which comes out of the Catholic intellectual tradition, requires that war be waged by a legitimate authority, that it be in a just cause, in response to which war is both proportionate and the last resort, that it have some prospect of success and that those who wage it have the right intention. I believe that both the invasion and present military operations in Iraq meet those criteria. Here, I will provide a brief justification of that judgment.

Was the Iraq War waged by legitimate authority? Our government has the responsibility of the common good of the United States (Catechism §2309), so this criterion was met. Hopes that judgments about national security can be made by the United Nations hardly survive the experience of the Srebrenica Massacre in July 1995.

Was there a just cause? The invasion has to be seen against the backdrop of the liberation of Kuwait. The armistice which ended that war reasonably demanded, among other things, that Iraq destroy its remaining stockpiles of chemical weapons and agree not to develop nuclear weapons. What finally became of Saddam Hussein’s chemical weapons remains a matter of guesswork. What is clear is his blatant violation of the conditions of the ceasefire. In 2003, most observers thought that he still had chemical weapons. His nuclear ambitions also were a matter of legitimate concern.

Iraqi compliance was important because of Hussein’s history of aggression (invasions of Iran in 1980 and Kuwait in 1990) and his history of the use of chemical weapons (against Iran and against Iraqi Kurds). That history was reason enough to demand that he give up chemical weapons and nuclear ambitions. Compliance was made even more urgent by his sponsorship of terrorism (documented in the recently released report of the Iraqi Perspectives Project, “Saddam and Terrorism”).

Thus, when President George W. Bush launched his war on terrorism in 2001, Hussein found himself, as a sponsor of terrorism, on the wrong side.

Was invading Iraq the last resort in enforcing chemical disarmament and blocking Hussein’s nuclear ambitions? Other methods had been tried. Economic sanctions were imposed in 1991, but Hussein managed to deflect the harm they did onto Iraq’s citizenry. The United Nations was unable to run the “Oil for Food” program without corruption. Attempts to reform the sanctions regime were blocked by Russia, and support for its continuation was crumbling. The limited use of military force in response to the expulsion of U.N. arms inspectors (Desert Fox in 1998) also was ineffective.

By late 2002, the United States faced three options: (1) to end sanctions, allowing Hussein to resume his chemical and nuclear weapons development programs (as the Duelfer Report showed he had every intention of doing), (2) to maintain the sanctions regime, inefficient and ineffective as it was, or (3) to threaten military action. Somehow, critics of Bush’s decision to go to war never say which of the other options they would have chosen.

Bush’s threat of force finally secured some pretence of cooperation from Hussein, but not the reality. At that point, a reasonable threat having been made, the threat had to be carried out. Failure to do so would have made future threats less credible and future wars, consequently, more likely.

Did resort to war meet the criterion of proportionality? It was reasonable to believe in advance that it would. Although innocent people would die as a side effect of the war, innocent people were dying as a side effect of the sanctions. Innocent people also were dying as a direct effect of Hussein’s approach to government. Human Rights Watch estimates that Hussein killed as many as 290,000 people over 20 years. As a result of the post-invasion war against Iraq by al-Qaeda, the death rate in Iraq has not decreased by much, but it has not gone up, either.

As expected, the war brought many good effects to Iraq, such as freedom of religion and political liberty – both of which returned to Iraq in 2003 – and the prospect of reintegrating Kurdistan with the rest of Iraq. As Bush said in London in November 2003 when asked to comment on the protests against his visit: “I’ve noticed that the tradition of free speech … is alive and well here in London. … They now have that right in Baghdad, as well.”

Was there a prospect of success? The immediate objective – removal of a regime that supported terrorism and sought nuclear weapons – was achieved quickly. I address the matter of longer-range objectives below.

Was war waged with the right intention? No serious critic has offered any reason to doubt this.

Al-Qaeda’s attack on Iraq beginning in 2003 changes the analysis above in one key respect. The cause that justified the invasion of 2003 was the danger posed by Iraq’s continued unjust violation of the conditions of the ceasefire of 1991. The just cause for fighting now is different. The current, democratically elected government of Iraq has asked for our help in fighting the terrorists who now bomb pilgrimages, funerals and marketplaces.

Surely fighting against such terrorists constitutes a just cause. Those terrorists are already waging their war against the Iraqi people. (They could not have  expected to kill GIs at the Golden Mosque or at the Baghdad pet market.) There is no resort but for someone to fight against them. Since Iraq is still rebuilding its army and police force, for the time being that means us, along with our British, Polish, Georgian and other allies. And, as the Petraeus-Odierno strategy has shown, there is a real prospect of success. The number of civilians and soldiers killed by the enemy has fallen sharply. Equally important, key pieces of legislation have now been passed by the Iraqi parliament, promising progress on the political front.

Both the original invasion and the continuation of the war today meet the criteria of the Just War Theory.

Further Reading: Both The Ethics of War (Manchester University Press, 1997) by A. J. Coates and Morality & Contemporary Warfare (Yale University Press, 2001) by James Turner Johnson provide helpful insight on this topic. And for a revisionist account with which I disagree on a number of points, there is Just & Unjust Wars (Basic Books, 1977) by Michael Walzer.