While the US-Russian deal to dismantle Syria's chemical weapons is a welcome sign that diplomacy has a central part to play in this crisis, the retreat from early talk of military action also suggests a growing reluctance on the part of the US and UK to intervene directly in the Middle East. Whether this is a good or a bad thing, it is certainly something new. These countries between them have played such a pivotal role in maintaining the balance of power in the region for more than a century and a half that uncertainty about their future intentions is bound to provoke searching questions and a degree of apprehension about the future.
Is intervention fatigue leading, at least in part, to the strategic disengagement of Anglo-American power from the world's most sensitive and conflict-prone region? What does it mean for the capacity of the international community to contain or resolve serious conflicts like Syria? What new mechanisms and relationships might be needed to guarantee regional stability if the US and its allies are less willing to become directly involved?
Of course, times change and so do the calculations countries make about their security interests. Britain had already ceased to be a global empire with a commitment to defend the sea routes to Asia by the time it withdrew from East of Suez in 1971. That mission was taken up by the United States as its Cold War rivalry with the Soviet Union intensified and it moved from being the world's largest producer of oil to being the world's largest importer. The Carter Doctrine formalised Washington's resolve to prevent the Gulf from falling under the control of another power.
Similarly dramatic changes in political and economic context continue to reshape American and Western perceptions of their interests in the Middle East today. These include concerns about military overstretch following the costly deployments in Iraq and Afghanistan, new scepticism about the effectiveness of hard power in achieving desired political outcomes, the prospect that unconventional oil and gas extraction will enable America to achieve energy independence once more, the Asian Pivot in US foreign policy and the effects of the ongoing fiscal crisis in constraining the resources and changing the priorities of Western governments.
Coming as it does at a moment of Western doubt and introspection, the civil war in Syria is significant because far more than Libya, or even Egypt, it has the capacity to draw other countries into a wider regional conflict. Syria sits across multiple geopolitical fault lines, linking the security problems of the Levant with those of the Gulf region through its proximity to the fragile states of Lebanon and Iraq, its diverse religious mix, its strategic alliance with Iran and its hostile relationship with Israel.
The risk of wider instability is increased by the tendency of the main regional players - particularly Saudi Arabia and Iran - to see the Syrian conflict in competitive, zero-sum terms. If neither side thinks it can afford to lose then the region is in danger of becoming trapped between a stalemate that prolongs humanitarian suffering or a victory for one side that upsets the balance of power with unforeseen and potentially destabilising consequences. An outcome that left Iran feeling more vulnerable and isolated, for example, could end hopes of a deal over its nuclear programme, fuelling further conflict and the proliferation of weapons of mass destruction.
It is clear from the British Parliament's vote against military action and the hesitancy with which US Congressional leaders approached President Obama's request to approve the limited use of force that Western intervention in the Syria is now off the agenda. This leaves diplomacy as the only realistic means of bringing the conflict to an end in a way that ensures the long-term security of the region. If the US, supported by Britain, is no longer in the business of intervening at the level required to change outcomes directly on the ground, then the only alternative to increased regional competition and rivalry is the creation of a concert of powers willing to share the task of restoring order by bringing their various Syrian allies to the negotiating table.
Instead of pursuing maximalist objectives at the expense of each other, the main external powers (the US, Britain and Russia) and main regional powers (Saudi Arabia, Turkey and Iran) need to see a common interest in sponsoring a peaceful settlement that protects the interests and rights of all sides. This will necessarily involve compromise and an element of risk-taking on the part of everyone involved. The West will have to live with a settlement that falls short of democratic perfection. Iran will have to accept power sharing arrangements that reduce the influence of their allies. The US and Saudi Arabia will need to find ways to develop a working relationship with the government in Tehran.
Perhaps the deal between Russia and the US is an early sign that a concert of powers could indeed provide a viable basis for resolving the Syria crisis and managing the wider security affairs of the Middle East more effectively in the future. If so, it presupposes continued Western engagement, albeit at a level that fits with the new reality of limited resources and changing foreign policy priorities. There is relief today that a negotiated solution to the chemical weapons threat in Syria has been found. But opinion in the Middle East will be looking for a sign that the United States and its allies remain committed to playing a leading role in the region for the long-term.