Editor's note: Mona Yacoubian is a senior adviser on the Middle East at the Stimson Center, a nonprofit and nonpartisan think tank that studies peace and security challenges around the world.
(CNN) -- The recent call by the United States and Russia for an international conference on Syria offers the best chance for a peaceful resolution to the escalating conflict that has claimed more than 70,000 lives and turned an estimated 1.4 million Syrians into refugees.
The peace talks, proposed May 7 by U.S. Secretary of State John Kerry and Russian Foreign Minister Sergey Lavrov, face significant obstacles from the recalcitrant Syrian regime of President Bashar al-Assad and a fragmented opposition.
Nonetheless, the U.S.-Russian diplomatic Hail Mary could finally begin to shift the deadly dynamics of the 2-year-old Syrian conflict from deepening militarization toward a political solution designed to end the horrific violence.
So far, Russia has been an important backer of the Syrian regime, supplying weapons and blocking U.N. sanctions against the government. President Barack Obama has called for al-Assad to step aside but has resisted providing the rebels with weapons that he fears could end up in the wrong hands.
Now Washington and Moscow realize that Syria's sectarian civil war has entered a dangerous phase. Israel's recent airstrikes inside Syria underscore the potential for the conflict to erupt into a broader regional conflagration. Spillover into neighboring Lebanon and Iraq has provoked destabilizing sectarian violence.
Inside Syria, intensified fighting and sectarian cleansing could presage the country's fragmentation into sectarian enclaves. Add to this the likely use of chemical weapons and the growing influence of groups affiliated with al Qaeda. It is no wonder that the United States and Russia might finally put aside their differences on Syria to forge a consensus on how to end the crisis.
But U.S.-Russian rapprochement is the easy part. Resolving Syria's complex conflict will require substantial diplomatic ingenuity against long odds.
A peace conference would build on the June 2012 Geneva Plan, a U.N.-brokered agreement that established a road map for Syria's peaceful transition. The plan quickly faltered when the U.S. and Russia could not agree on al-Assad's role, a detail left purposefully ambiguous. The Syrian opposition continues to insist al-Assad must go as a precondition for any transition talks. Al-Assad refuses to entertain any discussion of his exit.
Washington and Moscow -- along with their regional allies -- will need to exert pressure on the Syrian opposition and regime respectively to come to the negotiating table. In a notable indicator that transition talks on Syria might be gaining wide support, Iran and Jordan have issued a joint statement endorsing such talks.
But even if America and Russia succeed in convening a peace conference, it is far from clear that the Syrians around the table will wield sufficient influence over the forces fighting on the ground.
Indeed, the Syrian crisis now runs far deeper than the question of al-Assad's fate. The sectarian hatreds unleashed inside Syria will demand far greater international involvement.
An international peacekeeping force will likely be needed to ensure against reprisals and continuing communal violence. Extensive peace-building efforts -- including cross-sectarian dialogue, national reconciliation talks and transitional justice structures -- will be essential elements for Syria's long road to peace. Involvement by the U.S. and Russia will be critical to garnering international support and resources to back these efforts.
Finally, in pursuit of Syria's peaceful transition, Washington and Moscow must begin to address the wider regional tensions that have fed and been exacerbated by Syria's crisis. The United States, in particular, must leverage its regional influence to tamp down mounting sectarian tensions in Iraq and Lebanon.
Rejuvenating the Middle East peace process is another key element that could enhance stability, as are talks underway between the Turkish government and Kurdish rebels to resolve their decades-long conflict. Iran's role as Syria's staunchest ally, as well as its deepening shadow war with Israel, cannot be ignored.
Given the significant challenges, the odds that the U.S.-Russian peace conference gambit will succeed are slim. Yet, in a universe of bad options on Syria, peace talks sponsored by America and Russia merit the international community's full backing.
Military options -- arming the rebels, airstrikes and no-fly zones -- will likely be the fallback if this new peace effort fails. But each of these choices carries significant risks, not least the possibility of greater civilian casualties and lengthening of the conflict.
Before forging ahead with actions to escalate the fighting and the bloodshed in Syria's mounting tragedy, diplomacy should be given another chance.
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The opinions expressed in this commentary are solely those of Mona Yacoubian.