The is the latest episode in a long and torturous saga, set out in mindnumbing detail over acres of newsprint, covering the questions of whether Britain knew Iraq did not possess Weapons of Mass Destruction, whether the Prime Minister knew that a war might be illegal, etcetera, etcetera. One might be forgiven for thinking that these questions are particularly complicated. Happily they are not, and we can satisfy ourselves of the answers in pretty short order.

Fortunately for the unenlightened layperson, international law is crystal clear on where the use of armed force is legitimate. The UN Charter permits it in two instances: either in self-defence, or when authorised by the security council. The latter requires no discussion – at least not unless the other members of the council somehow authorised the war without realising it - so lets proceed straight to the former: self defence.

Did the US and the UK invade Iraq in self defence? The fact that the question is even asked, much less that it has apparently been agonised over for over two years by the great and the good, gives the measure of our political culture in stark and depressing terms. Consider the very idea that America, the greatest military power in all history, needed to defend itself from the tin-pot dictator of a crippled third world country. A country that did not control its own airspace, that had been bombarded at will by America for over a decade, whose infrastructure had been smashed, whose people were starving, was about to rise up and….and do what exactly? Send its armies to march on Washington? The notion was palpably absurd from the start. And whether or not the claims on Iraq’s WMD were true was an utter irrelevance. If Iraq had possessed WMD it would have joined a group of nations, like North Korea and Iran, which have a degree of military power and poor relations with the west, but know full well that to instigate a war with such an enemy is to commit instant suicide.

The Iraq war was illegal. Moreover, since it was patently not fought in self defence, it follows that the war was a crime of aggression. “Aggression”, according the UN General Assembly Resolution 3314, passed in the wake of Vietnam, “is the use of armed force…in any matter inconsistent with the Charter of the United Nations”. After World War Two the court at Nuremberg described the war of aggression as “essentially an evil thing…to initiate a war of aggression…is not only an international crime; it is the supreme international crime differing only from other war crimes in that it contains within itself the accumulated evil of the whole”. Associate US Supreme Court Justice Robert Jackson, chief prosecutor at the trial said that “no political or economic situation can justify” the crime of aggression, which was “the greatest menace of our times”.

Elizabeth Wilmshurst, deputy legal adviser to the Foreign Office, viewed the coming invasion in precisely these terms when she resigned her post in March 2003. In her resignation memo, Wilmshurst was unequivocal: “an unlawful use of force on such a scale amounts to the crime of aggression”. Mindful of the wide and serious consequences that would follow, she went on to say that she could not, in good conscience, “agree with such action in circumstances which are so detrimental to the international order and the rule of law”. Wilmshurst’s stand was praiseworthy and her opinion an educated one; but her’s, as we have seen, was nevertheless a statement of the obvious.

Yesterday, Tony Blair sounded like a man tired of the seemingly endless speculation regarding the war’s legality. I sympathise. There is no requirement for further disclosures, nor further judicial enquiries on the subject. Both our government and the American government are guilty of committing “the supreme international crime”; initiating a war of aggression. The electorate, on May 5, can now move to sentencing.