To intervene or not to intervene? That is the question increasingly on the minds of world leaders at the start of the 21st Century.
To President Bush's doctrine of pre-emptive action, we now have to add British Prime Minister Tony Blair's doctrine of "international community."
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This is a kind of half-way house between the freedom of action Mr Bush seeks to preserve and the rules of the United Nations Charter which allow intervention only in certain circumstances, such as reversing an act of aggression.
It is highly unlikely that the UN would want to go too far down the interventionist path. The UN exists to try to make individual action unnecessary.
And to some a doctrine of international community is a doctrine of international interference.
But the old rules are already under strain.
Nato's attack on Serbia over Kosovo in 1999 established the rule of a humanitarian intervention. It followed the worldwide guilt felt at the failure by the UN, or anyone else, to intervene in Rwanda.
Nato's said its Serbia campaign was a humanitarian intervention
Now Mr Blair wants to take the process further.
International terrorism post-11 September and the spread of weapons of mass destruction require a further redefinition of the rights of a nation-state, he argued in a speech on Friday.
He even mentioned the Treaty of Westphalia in 1648. That basically ended the religious wars in Europe and began the modern system of the nation-state, whose rights, he suggested, should be further curtailed.
He wondered whether international law should not be developed to avoid situations where "a regime can systematically brutalise and oppress its people and there is nothing anyone can do, when dialogue, diplomacy and even sanctions fail, unless it comes within the definition of a humanitarian catastrophe".
Tony Blair in fact first mentioned his doctrine of international community (and world figures like to be known for their doctrines) in a speech in Chicago in 1999. It was at the time of the Kosovo war.
'Five rules' for intervention
It was a speech which Saddam Hussein should have read. It illustrated Mr Blair's inclination for action.
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He outlined five rules for intervention - be sure of your case, exhaust all other options first, ask if military operations can be "sensibly" undertaken, prepare for the long-term and identify if your interests are involved.
Ideally, Mr Blair suggested in both speeches, the UN would lead the way. But the implication is that individual countries should act if the UN did not.
His problem of course is that "intervention" for some is "aggression" for others. His speech is also under attack from his critics for being too much of a justification of the war in Iraq.
UN's 'wise men'
Meanwhile, the UN itself is also trying to redefine intervention.
Last September, the UN Secretary General, Kofi Annan, set up a committee of "wise men and women" to make recommendations about the UN's future role. It will report this December.
There are 16 members of the committee, an array of the international great and the good (and some say the deja vu).
The members include President Bush senior's National Security Adviser Brent Scowcroft, who opposed the latest war against Iraq, and former Norwegian Prime Minister Gro Harlem Brundtland, who always has the interests of the developing world at heart.
It is not a panel likely to recommend pre-emptive military action.
Lord Hannay, a former senior British diplomat and another member, indicated the limits of the committee's aims.
"The UN should get involved with countries under stress," was how he put it to the BBC.
"We support a collective response to stop a state from sliding down the slope," he said.
Lord Hannay pointed out that there were "different perceptions" about what a threat was in different parts of the world. To some, poverty and Aids were the problem, not terrorism.
The thorn the committee may or may not grasp is the UN's Article 39 which itself accepts that the UN can act in advance of an overt act of war by one state against another.
"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," it states.
This article means that the UN can take its own collective pre-emptive action - and of a military kind. It could one day declare that, say North Korea, is a "threat to the peace."
That is really what Mr Bush and Mr Blair are on about. If the UN does not act, they argue, then individual states may do so themselves.
That in turn would be a long way from Article 2 of the UN Charter which says: "All Members shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any state."