Like all conflicts in which the West is nowadays involved, the war in Libya is asymmetric. At the weekend, French, US and UK forces began to hit Muammar Gaddafi's air defences. And the Libyan dictator is fighting back, not with his own planes and missiles, but with propaganda.

The regime in Tripoli is claiming that 48 civilians were killed and a further 150 wounded by the initial Western strikes. Those figures have not been verified and the Gaddafi regime is likely to be exaggerating the numbers killed. Something similar took place in the 1999 Kosovo war, when Nato planes, enforcing a no-fly zone, were accused of killing a large number of Serbian civilians in the process.

Human Rights Watch was subsequently able to verify around 500 civilians killed by Nato bombing. But the Serbian authorities, at the time, claimed a much higher number. The purpose of these inflated totals was to rally the Serbian people against an external aggressor and also to demoralise the West, which justified the operation as a means of saving lives.

Ultimately, those tactics from the Serbian regime failed to deter Nato in the Balkans. But such an approach might prove more effective in North Africa. Reports of civilian casualties (verified or not) could be even more toxic in the Arab world than they were in Kosovo, because of the history of Western interference in the region. Yesterday, Saif Gaddafi gave an interview to an American news broadcaster, invoking the invasion of Iraq in 2003. His father condemned "crusader aggression" on Libyan state TV. Such lines coming from vicious despots like the Gaddafi clan are cynical in the extreme. And so far they have been dismissed by the Arab world, where the Libyan dictator has no constituency. But the West should not underestimate how effective such propaganda could be, particularly if civilian deaths are verified over the coming days. The Arab League's sharp criticism of the air strikes yesterday was a serious blow for the Western military coalition. The League's support for a no-fly zone was important in getting UN resolution 1973 through the Security Council. This apparent change of heart inevitably undermines the legitimacy of the intervention. And yesterday's critical words from Russia, China and the African Union are a setback for a similar reason.

Allied to dangers of a reversal in the propaganda war is the threat of mission creep on the part of the Coalition. Western warplanes are primed to attack Gaddafi's ground forces if they advance on the opposition bases (and indeed this seems to have begun already). But will they attack pro-Gaddafi forces if the opposition takes the fight to Tripoli? That would make matters much more complicated and risk disastrous mistakes. It can be very hard for pilots to distinguish between two sides in a conflict from a great height. The presence of Western special forces in Libya would make identification of the right targets easier, but the UN resolution forbids any military intervention on the ground.

If this operation is to be strictly limited, is the Western coalition prepared to tolerate Gaddafi remaining in power? Is it prepared to see the creation of a Libya divided between pro-Gaddafi and pro-opposition forces? Admiral Mike Mullen, the head of the US military's Joint Chiefs of Staff, recognised that such a stalemate was a "possibility" yesterday. But he did not elaborate on how the coalition would respond to such an outcome.

The West is making policy in an ad hoc manner. That is an understandable approach, given the sensitive politics of humanitarian intervention. But it does carry considerable dangers. Clear thinking must take place behind the scenes about the endgame for this operation. Without such thought, the outside world risks making the situation in Libya worse, not better.