Three different types of arguments were used to justify the 2003 Iraq War. The first was based on the requirements of national security. Iraq was believed to be developing deadly weapons which it might use against neighbouring states or hand over to terrorist groups such as al-Qaeda. A second argument was based on international security. Iraq was supposed to comply with a series of UN Security Council Resolutions and was failing to do so, thereby undermining the credibility of the leading international institutions. The third argument was based on human security. The Iraqi people had suffered too long under a tyrannical regime and this was an opportunity to overthrow it and replace it with something much better.

It was also the case, of course, that these arguments were matched by opponents of the war. The national security argument against war not only questioned the existence of weapons of mass destruction (WMD), or their relevance if they did exist, but also argued that the occupation of a Muslim country would provoke support for and the ire of terrorist groups. The international security argument noted the divisions within the Security Council, and the consequent risk to the credibility of the institution should leading states go to war regardless of the majority view. The human security argument questioned whether people could be liberated by means that would in themselves be bound to cost many innocent lives.

These arguments were all in play prior to the war. Afterwards, as it became apparent that there were no WMD to be found, the pro-war case increasingly depended on the human security arguments.