Although Bashar al-Assad is still clinging on in Syria – despite nearly two years of fighting and an estimated 40,000 deaths – there are signs that his grip on power is slipping. Unco-ordinated, hit-and-run rebel raids have been replaced by targeted attacks on military bases; large swathes of territory, particularly in the north of the country, are now outside of Damascus's control; even the regime's chief spokesman is said to have fled the country.

But Assad is still far from beaten. And as his desperation increases, he becomes more dangerous than ever. The violence is already intensifying, with disturbing reports of cluster bombs dropped in civilian areas. More alarming still are intelligence reports suggesting that the regime may be considering using its chemical weapons. Unlike Saddam Hussein's weapons of mass destruction, Syria's chemical arsenal is no mirage: after decades of investment, Damascus is known to have a cache including mustard gas and the nerve agent, sarin.

There were suitably strong words from the international community in response. Barack Obama warned that "the world is watching". There will be "consequences" if chemical weapons are used, he said, and Assad "will be held accountable". Anders Fogh Rasmussen, the Nato Secretary General, echoed the US President's tone, promising an "immediate reaction from the international community".

What neither spelled out, however, was what such consequences might be. Meanwhile, for all the tough talk, the international community remains deeply divided over Syria. Even Nato's decision to send anti-missile batteries to protect Turkey's long Syrian border from stray mortar shells – under discussion in Brussels yesterday – met with disapproval from Russia, a long-standing ally of Damascus. Vladimir Putin tartly dismissed Nato assurances that the Patriot systems are purely defensive with the observation: "If you have a gun on a wall, eventually it will be fired."

Against such a background, it would be easy to conclude that the latest round of condemnations are no more meaningful than all those that preceded them. But for all the cries that "something must be done", there is still no better option than concerted diplomatic pressure and continued efforts to ease the appalling humanitarian cost of the conflict.

Those that would press for military intervention in Syria make the dangerous assumption that such an involvement could only improve the situation. Yet experience – most obviously in Iraq and Afghanistan – suggests otherwise. Nor is arming the rebels any more certain to help. To suggest that only the quality of their weaponry stands between the opposition and success is to underestimate the tenacity of the Assad regime. Equally, it risks overestimating the coherence of the rebels.

Despite recent moves to establish a unified movement, the opposition in Syria remains highly fragmented. Indeed, the National Coalition of the Syrian Revolutionary and Opposition Forces put together last month (and swiftly recognised by Britain as the "sole legitimate representative" of the Syrian people) almost immediately descended into rows over its membership. Amid such confusion, and with any number of different groups fighting on the ground, the chances of exacerbating the violence are simply too great.

Thus far, then, the balance of risk remains tilted away from direct intervention. Sanctions, humanitarian aid and all possible assistance towards a political solution are the only responsible course. Were Assad to use his chemical weapons, that might change. Until then, a phoney war is still better than a real one.