They have committed themselves to a war, but they have no plans for what happens after tomorrow night.
They swear that they will never put ground troops into Libya, so their strategy consists solely of hoping that air strikes on Colonel Gaddafi's air defence systems (and on his ground forces when they can be targeted without killing civilians) will persuade his troops to abandon him.
They don't even have an agreed command structure.
So why is this coalition of the willing (which has yet to find a proper name for itself) doing this?
Don't say it's all about oil.
That's just lazy thinking: all the Western oil majors are already back in Libya.
They have been back ever since the great reconciliation between their governments and Gaddafi in 2003.
That deal was indeed driven partly by oil, although also in part by Western concerns about Libya's alleged nuclear ambitions. (Gaddafi played his cards well there, because he never really had a viable nuclear weapons programme.)
But do you seriously think that Western governments have now launched this major military operation merely to improve the contractual terms for a few of their oil companies?
Maybe it's just about local political advantage, then.
President Nicolas Sarkozy of France was the driving force behind this intervention, and he faces a re-election battle next year.
Is he seeking credit with French voters for this humanitarian intervention?
Implausible, since it's the right-wing vote he must capture to win, and saving the lives of Arab foreigners does not rank high in the priorities of the French right.
Prime Minister David Cameron in Britain was the other prime mover in the Libyan intervention.
Unless the coalition government he leads collapses (which is quite unlikely), he won't even have to face the electorate again until 2014.
So what would be the point in seeking political popularity with a military intervention now?
Even if that were a sure route to popularity in Britain, which it is not.
As for Barack Obama, he spent weeks trying to avoid an American military commitment in Libya, and his secretary of defence, Robert Gates, was outspoken in denouncing the idea.
Yet there they all are, intervening: France, Britain, the United States, and half a dozen other Western countries.
Strikingly unaccompanied by Arab military forces, or indeed by anybody else's.
There is no profit in this for the West, and there is a high probability (of which the interveners are well aware) that it will all end in tears.
There is the danger of mission creep, there is the risk that the bombing will kill Libyan civilians, and there is the fact that many of the countries that voted for Security Council Resolution 1973, or at least abstained from voting against it, are already peeling away from the commitment it implied.
They willed the end: to stop Gaddafi from committing more massacres.
They even supported or did not oppose the means: the use of all necessary measures to protect Libyan civilians, which in diplomatic-speak means force.
But they cannot stomach the reality of Western aircraft bombing another Third World country, however decent the motives and however deserving the targets.
So why have the Western countries embarked on this quixotic venture?
Indians feel no need to intervene, nor do Chinese or Japanese.
Russians and South Africans and Brazilians can watch the killing in Libya on their televisions and deplore Gaddafi's behaviour without wanting to do something about it.
Even Egyptians, who are fellow Arabs, Libya's next-door neighbours, and the beneficiaries of a similar but successful democratic revolution just last month, haven't lifted a finger to help the Libyan revolutionaries.
They don't lack the means - only a small fraction of their army could put an end to Gaddafi's regime in days - but they lack the will.
Indeed, they lack any sense of responsibility for what happens to people beyond their own borders.
That's normal.
What is abnormal is a situation in which the failure to intervene in Rwanda to stop the genocide is still remembered and debated 15 years later.
African countries don't hold that debate; only Western countries do.
Western countries also feel guilty about their slow and timorous response to the slaughter in former Yugoslavia in the 1990s.
Nobody else does.
Cynicism is a necessary tool when dealing with international affairs, but sometimes you have to admit that countries are acting from genuinely selfless and humanitarian motives.
Yes, I know, Vietnam, and Iraq, and 100 years of US meddling in Latin America, and 500 years of European imperial plunder all around the world.
I did say "sometimes".
But I think this is one of those times.
Why is it only Western countries that believe they have a duty to intervene militarily, even in places where they have no interests at stake, merely to save lives?
My guess is that it's a heritage of the great wars they fought in the 20th century, and particularly of the war against Hitler, in which they told themselves (with some justification) that they were fighting pure evil - and eventually discovered that they were also fighting a terrible genocide.
This does not mean that all or most of their military adventures overseas are altruistic, nor does it mean that their current venture will end well.
In fact, it probably won't.
No good deed goes unpunished.
Gwynne Dyer is an independent London journalist.
