A bombing campaign against Syria could have incalculable consequences

We are in August, which rather than TS Eliot’s April, seems to be the cruellest month. This time next year will mark the centenary of the outbreak of the war from which all the calamities of the rest of the century sprang.

The Nazis, the Soviet Union and Iraq all chose August as an invasion month. This August has brought us the horror of chemical warfare in Syria, where the prime suspect is the Assad regime.The use of chemical weapons is banned by the Geneva Convention of 1925; their use against civilians constitutes a crime against humanity.

Of course their use is profoundly shocking and repulsive. But while the Obama administration talks of a red line being crossed and the sound of war drums can be heard, let us consider whether the deaths, however grim, of some hundreds by chemical weapons are worse than the 100,000 deaths (of which about half are civilians) to date by indiscriminate massacres and the prolonged shelling of civilian areas by Assad’s forces? Don’t these war crimes also deserve a red line?

While military action now seems inevitable, its legal basis looks highly dubious. We are faced with the near certainty of a Russian (and Chinese) veto of any UN Security Council Resolution authorising the use of force, given what they perceived as Western bad faith, mutating authorisation for limited airstrikes for humanitarian purposes into an air campaign actively aimed at forcing Gadafy from power.

The absence of such a resolution will render any military action illegal, of course, as in Iraq, but the US and UK will no doubt claim overriding humanitarian need as trumping international law. But given the Western debacles in Iraq and Afghanistan and the US and the UK's reluctance to introduce ground troops, how is this humanitarian need going to be met? By degrading Assad's air bases or bombing his chemical arms dumps? What might the effect of the latter be on surrounding areas and local communities? And what is the risk of such weapons being looted? The regime itself would feel no compunction about using any surviving toxic material.

It might be argued that diplomacy has failed. Certainly we are a long way from a power-sharing formula à la Good Friday Agreement. One of the many problems is that this has become not just a sectarian conflict but a proxy war for the wider Sunni/Shia bifurcation. Iran and the Lebanese Hizbullah supporting their Shia co-religionists of the Assad regime while the opposition can count on Sunni jihadists and Saudi Arabia for support. A truly distasteful choice.

So if diplomacy is deemed to have failed, what are the Western war aims? Retribution may satisfy critics and possibly deter a repetition but will not of itself bring about a definitive resolution. Tipping the balance in the rebels’ favour looks to be the unspoken aim; in other words the real agenda is once again regime change.

But change to what? The Free Syrian Army has little or no proper military structure. In terms of being an effective fighting force, it has been overtaken by foreign jihadists and the al-Qaeda affiliate Jabhat al-Nusra: in fact there is a civil war within a civil war between secularists and Islamists, with the latter now holding the whip hand. Meanwhile the New York Times recently reported that nowhere in rebel-held territory is there a secular fighting force to speak of. Instead Sharia courts are dotted throughout. All of which underlines the reality that there are no moderate groups capable of filling the power vacuum in the event of the collapse of the regime. So is the West facilitating regime change only to see Islamists in power in Damascus?

The borders of Syria, like the rest of the Levant, were drawn to deal with the collapse of the Ottoman Empire during the First World War. The draughtsmen, two British and French diplomats, Sykes and Picot, divided the post-war Ottoman Empire into respective zones of influence. Syria was as a result less a nation state in character, more an agglomerate of religious and clan interests with a mix best described as unholy: Sunni, Shia (Alawites), Kurds, Christians, Druze, Armenians and Turks co-existed under the oppressive autocratic regimes of the two Assads. But the sectarianism which has now been unleashed has borne down on all, particularly on minorities, including Christians. Given the extreme bitterness of the conflict, is it any wonder that the end of the Sykes-Picot agreement is being increasingly mooted? It is not only the survival of the state of Syria that is at stake: Iraq could well revert to its three Ottoman provinces. And Lebanon, which has already felt the force of the Syrian conflict, could go the same way.

Obama and Cameron have now raised expectations of military action to such a degree that anything less than the use of force will make them look weak. Obama has up till now been cautious. For a reason. And all the reasons for his reluctance to get drawn into the Syrian quagmire are still in place. The choices are grim. Making the wrong one, as in Iraq, is bound to lead to unforeseen consequences. With muddled war aims and a lack of legitimacy, the justification for military action must be about more than cutting a strong figure.

A bombing campaign will destabilise an already fragile and fractured region and quite possibly beyond. Iran and Hizbullah cannot afford to allow their Shia (Alawite) ally to be overthrown by Sunnis. Israel might hope that a military attack on Syria could allow them to launch an attack on Iran's suspected nuclear arms facilities with impunity. Meanwhile Russia, which has defended the Assad regime for decades now, cannot afford to stand idly by and see its only client in the Middle East go under. This possible chain may appear far-fetched but similar alliances and miscalculations led to the Great War. The ghosts of August 1914 still roam.

Sir Ivor Roberts, president of Trinity College, Oxford, was British ambassador to Ireland from 1999 to 2003.