Without a no-fly zone, the Syrian civil war will burn us all

On top of fuelling sectarian tensions and endangering Syria's democratic transition, a large jihadist presence raises the terrifying prospect of Assad's chemical and biological weapons falling into the hands of al-Qaeda-affiliated groups.

The obvious obstacle to a no-fly zone is resistance from Russia and China in the United Nations Security Council (UNSC). The mission creep that followed their abstentions on the UNSC resolution authorising the Libyan no-fly zone left a bitter taste for these veto-wielding, anti-interventionist world powers.

The historically close ties between Moscow and Damascus make getting movement on a no-fly zone even harder.

Russia is heavily invested in the survival of the Assad regime. The Russian naval facility at Tartus on the Mediterranean coast is the only base of its kind beyond the territory of the former Soviet Union, and Syria was Russia's second-largest arms customer in 2011.

Nevertheless, the Syrian equation is now also changing for Russia.

Despite the Assad regime's determined fight for survival, the fall of Damascus is more a question of when, not if. The regime has lost control of much of Syria's frontier with Iraq and the Kurdish north-eastern regions, while rebels are advancing in the southern province of Daraa.

The likely eventual collapse of the beleaguered Assad regime means that Russia stands to gain little from continuing its support. Even if Moscow throws its full diplomatic weight behind Damascus, it will probably still lose its partner, while also earning the ire of the new Syrian government.

For Russia, the Syrian calculation is clear. Lose Assad now and save a little face, or lose him later and face opprobrium.

Even if Russian and Chinese support for a no-fly zone can be won, the international community's options remain diabolical: non-intervention and an unrelenting civil war that leaves tens of thousands more civilians dead and traumatised, or a no-fly zone and regime change that could precipitate brutal reprisals against Assad's Alawite backers and the rise of an authoritarian Islamist state.

As grim as these Syrian scenarios might be, it is delusional to expect foreign policy dilemmas this serious to offer easy choices.

Instead of wishing the world was different, it is time for the international community to take a calculated risk, accept part of the burden of responsibility for regime change in Damascus, and impose a no-fly zone.