For one thing there is the United Nations Charter
CHAPTER VII
ACTION WITH RESPECT TO THREATS TO THE PEACE, BREACHES OF THE PEACE, AND ACTS OF AGGRESSION
Article 39
The Security Council shall determine the existence of any threat to the peace, breach of the peace, or act of aggression and shall make recommendations, or decide what measures shall be taken in accordance with Articles 41 and 42, to maintain or restore international peace and security.
Article 40
In order to prevent an aggravation of the situation, the Security Council may, before making the recommendations or deciding upon the measures provided for in Article 39, call upon the parties concerned to comply with such provisional measures as it deems necessary or desirable. Such provisional measures shall be without prejudice to the rights, claims, or position of the parties concerned. The Security Council shall duly take account of failure to comply with such provisional measures.
Article 41
The Security Council may decide what measures not involving the use of armed force are to be employed to give effect to its decisions, and it may call upon the Members of the United Nations to apply such measures. These may include complete or partial interruption of economic relations and of rail, sea, air, postal, telegraphic, radio, and other means of communication, and the severance of diplomatic relations.
http://www.un.org/aboutun/charter/chapter7.htmThe United Nations did not approve the war in Iraq, although Bush and Blair tried desperately to persuade it to do so.
It is a basic principle of English Common Law that the intentional taking life of another to preserve your own is a crime, unless the life is taken in self-defense. Self-defense requires, at a minimum, an imminent threat of death of sever bodily harm to ones self or another.
The DSMs are significant because they establish that in the eyes of the British the threat that Saddam posed to the UK and/or the US was not imminent enough to justify war. The DSMs also establish that the British did not believe that the situation in Iraq was an emergency that justified war. They urged Bush to obtain authorization from the UN to go into Iraq, but, based on the best evidence they could present, all they ever really got was a resolution to send the UN inspectors back into Iraq and decide whether war was justified based on the inspectors' report. Hans Blix reported to the UN that Saddam was reluctantly cooperating with the inspectors, but that the cooperation was not yielding as much information as desired.
He said:
One can hardly avoid the impression that, after a period of somewhat reluctant cooperation, there has been an acceleration of initiatives from the Iraqi side since the end of January.
This is welcome, but the value of these measures must be soberly judged by how many question marks they actually succeed in straightening out. This is not yet clear.
Against this background, the question is now asked whether Iraq has cooperated “immediately, unconditionally and actively” with UNMOVIC, as required under paragraph 9 of resolution 1441 (2002). The answers can be seen from the factual descriptions I have provided. However, if more direct answers are desired, I would say the following:
The Iraqi side has tried on occasion to attach conditions, as it did regarding helicopters and U-2 planes. Iraq has not, however, so far persisted in these or other conditions for the exercise of any of our inspection rights. If it did, we would report it.
It is obvious that, while the numerous initiatives, which are now taken by the Iraqi side with a view to resolving some long-standing open disarmament issues, can be seen as “active”, or even “proactive”, these initiatives 3-4 months into the new resolution cannot be said to constitute “immediate” cooperation. Nor do they necessarily cover all areas of relevance. They are nevertheless welcome and UNMOVIC is responding to them in the hope of solving presently unresolved disarmament issues."
Blix was later interviewed by NPR:
, March 16, 2004 · The leaders of the United States and Britain failed to exercise "critical judgment" in going to war against Iraq a year ago despite the lack of hard evidence that Iraq had weapons of mass destruction, says Hans Blix, the former chief United Nations weapons inspector in Iraq.
"If you sentence someone to death or you sentence someone to war, you'd better have some evidence," Blix tells NPR's Bob Edwards. "And we didn't feel there was evidence..."
Blix, whose new book is called Disarming Iraq, says he became doubtful about the existence of Iraqi WMD in January 2003. He says U.N. inspectors visited locations in Iraq that intelligence had indicated "as places where there would be weapons. And in none of these cases did we find any weapons."
http://www.npr.org/templates/story/story.php?storyId=1767468UN Resolution 141
http://wikisource.org/wiki/UN_Security_Council_Resolution_1441