Daunting task of destroying Syria's chemical weapons
The Syrian government's acknowledgement that it has a chemical weapons stockpile and is now, apparently, willing to destroy it under international supervision provides - at face value - a tantalising "win-win" option for US President Barack Obama.
The Russian-brokered deal holds out the possibility of destroying Syria's chemical weapons stocks in their entirety, while at the same time avoiding any US military action.
But appearances can be deceptive. The proposal raises an array of legal, technical and practical problems.
Dismantling Syria's chemical weapons infrastructure would take considerable time - even under the best of circumstances, and the situation on the ground in Syria is very far from being a benign environment.
The broad procedures for setting about such a task are well-defined and tested. The body that would most likely take on a key role is the Hague-based Organization for the Prohibition of Chemical Weapons - the OPCW.
This is the implementing authority for the Chemical Weapons Convention, which bans the development, production, stockpiling and use of these weapons.
Six of its staff members were involved with the UN-inspection team that has already been on the ground in Syria and the organisation's director general, Ahmet Uzumcu, says that his organisation stands ready to play a role if requested by the UN.
The exact process by which any Syrian disarmament initiative would get under way is for now unclear. Would it require a decision of the UN Security Council or the UN secretary general? Would Syria simply join the Chemical Weapons Convention?
Time is of the essence - some special interim arrangement might well be needed, but inspectors on the ground would clearly need some legal framework within which they would be working.
But the diplomatic and legal difficulties pale in comparison to the practical problems involved.
In a nutshell, what has to happen is that:
- Syria has to declare all of its stocks of chemical munitions and agents, and make a full accounting of its production facilities
- This information has to be studied and inspectors have to go in to carry out a base-line inspection, to verify that it is both correct and complete
- Munitions and so on have to be gathered into secure areas and ultimately be destroyed, a process that requires specialised plant and equipment
- Chemical weapons plants have to be monitored to confirm they have either been put out of use or converted for other purposes.
Libya provides an example of a country that made a sudden decision to abandon its chemical stockpile, sign-up to the CW Convention and then set about the process of dismantling and destruction.
In broad terms things went relatively smoothly, though progress was interrupted and ultimately delayed for months by the war that ousted Col Muammar Gaddafi - causing shortages of spare parts for the plant and the trashing of living quarters for inspectors and so on.
Some useful lessons were learnt.
But fundamentally Syria presents very different and unprecedented problems. For the OPCW and the international community as a whole, this would be a leap into the unknown.
First, the scale of the problem.
Syria has probably the largest active chemical munitions stockpile in the world. Intelligence provided by the French government suggests there is something in the order of 1,000 tonnes of agent in total: a mix of sulphur mustard, VX and sarin.
US sources suggest that there are at least 20 sites of interest - possibly considerably more. Some, like a plant near Safira in northern Syria, are very close to contested areas.
The context in Syria is far from benign. A full-scale civil war is raging. There are groups who would love to get their hands on chemical stocks and who would have no interest in making the international community's disarmament effort go smoothly.
Then there is the nature of the Syrian regime itself: secretive, in many ways fighting for its survival.
For Syria to sign up on the dotted line is relatively easy. The instrument of accession to the Chemical Weapons Convention needs to be signed - probably by President Bashar al-Assad himself; it is then deposited and some 30 days later Syria is a fully-fledged member of the treaty.
But then the whole declaration, verification and inspection process begins.
That could take months, raising all sorts of questions. How far can the Assad regime's declarations be trusted? Would they provide full access to facilities and stockpiles?
What about access to any other sites that intelligence suggested were linked to the chemical programme? And who would guarantee the safety of inspectors?
The problems are immense. This even before the gathering of munitions in secure locations or any thoughts of actual destruction.
This proposed deal, in the words of one leading weapons expert, is "deceptively attractive".
It may just get President Obama off a hook of his own making: if it genuinely pushes Syria down the road towards verifiable chemical disarmament it will help to establish a powerful precedent, that "you use chemical weapons and you lose them".
Mr Obama is no doubt hoping that a serious diplomatic effort now will enable him to rally support for military action later on if the disarmament effort stalls or collapses altogether.