Over the past few days, American officials have spent a lot of time studying the 1999 Kosovo conflict in which Nato launched weeks of air strikes without United Nations support and in the teeth of Russian opposition. The parallels with the situation in Syria today are readily apparent. The intervention 14 years ago was designed to protect the people of Kosovo from Serbian ethnic cleansing. In Syria, civilians in a Damascus suburb held by rebels fighting President Bashar al-Assad's regime have suffered in an equally barbaric manner from chemical weapons. It is tempting to believe the tactic that secured victory in Kosovo would achieve the same outcome in Syria. But matters are not that simple.
There seems very little doubt that the Syrian regime, indeed, crossed the "red line" laid down by President Barack Obama a year ago in using chemical weapons last week. Medecins Sans Frontieres says 3600 patients with symptoms of poisoning were treated at three hospitals it supports, and that at least 355 of them died. This represented a horrifying escalation in the conflict.
It was also completely unnecessary because after a long period of stalemate, the regime's forces seem to be gaining the upper hand over the rebels. The use of such weapons could only threaten to undo that by being the catalyst for Western military intervention.
However, President Assad, or whoever orchestrated the chemical attacks, may have gauged that the chances of a decisive response are minimal. If so, the message sent to the rebels by this ruthlessness would have an impact out of all proportion to the likely repercussions. There are several reasons for believing that may be correct. The Kosovo campaign involved 78 days of aerial bombardment. It is questionable whether any of the Western powers would relish that degree of engagement.
They also know Syria is a far more difficult proposition because of its sophisticated Russian-supplied anti-aircraft defences. Western planes would not be free to roam Syrian airspace. The strikes would, therefore, have to be through Tomahawk cruise missile strikes from warships stationed in the Mediterranean or aircraft firing rockets from outside Syria.
More than anything, however, there will be hesitation because as evil as the Assad regime has proved, the outcome of successful Western intervention could be just as calamitous. The Syrian conflict started as an uprising against a tyrannical government. But, increasingly, it has become a sectarian conflict, and the rebel forces have come to be dominated by anti-Western fundamentalists who have little interest in establishing a secular democracy. The strength and reach of al-Qaeda-linked groups such as the al-Nusra Front has caused the United States to delay dispatching lethal weapons to the rebels.
President Obama is well aware of the potential consequences. He has talked of being "mired in very difficult situations", a particularly dire possibility given America's long-term and ultimately unsatisfactory involvement in Iraq and Afghanistan. As such, any immediate Western response is likely to be limited to precision missile strikes against chemical-weapon storage areas or military infrastructure. That may restore President Obama's credibility somewhat and stop further chemical attacks. But it is unlikely to change the balance of the conflict. That will be achieved only by the sort of concerted action which occurred in Kosovo.
In a best-case scenario, such a campaign would force President Assad to talk peace before making way for a successor who would be happy to work within the framework of a secular state. At the moment, that is a long shot, not least because of Western governments' reluctance to become deeply entangled. Any other outcome, however, bodes ill for both them and the Syrian people.