"... One, as yet untried, diplomatic option would be to work under the auspices of the Chemical Weapons Convention (CWC) to rapidly remove chemical weapons from Syria. Negotiation and implementation of this action would bring the Syrian government into close engagement with the world community, and would involve the presence of UN inspection teams. When this process is under way, any use of chemical weapons in Syria could be unequivocally attributed, allowing appropriate international response. ...
If the session were successful, Syria would rapidly sign and ratify the CWC, accept the rapid removal of chemical weapons from its territory, and accept stringent inspections to verify its compliance. Why might the Syrian government agree to these actions? To some extent, Syria could be motivated by related actions by other countries, discussed below. The major motive, however, would be pressure from the Syrian government's allies.
Russia could be important in this respect, but the primary actor would be Iran. While Iran is a firm ally of the Syrian government, Iran's people have learned from bitter experience to abhor chemical weapons. Iran made a statement to the April 2013 CWC review conference, on behalf of Non-Aligned Movement (NAM) countries and China, including the passage:
Translation of this sentiment into an adequate level of pressure on the Syrian government could involve a bargain directly affecting four countries - Iran, Syria, Egypt, and Israel. Indirect participants would include the permanent members of the UN Security Council - US, UK, Russia, France, and China. The bargain would require each country to re-think entrenched positions and abandon some longstanding linkages among negotiating issues.
One part of the bargain would be that Syria, Egypt, and Israel rapidly become full parties to the CWC. In Syria's case, there would be a special arrangement for rapid removal of chemical weapons from its territory. Implementation of the CWC in Egypt and Israel could follow a normal schedule. To allow this agreement, Syria and Egypt would have to abandon their longstanding refusal to accede to the CWC until Israel accedes to the Nuclear Non-Proliferation Treaty (NPT) and dismantles its nuclear arsenal.
In return, Israel would make concessions about its nuclear arsenal, such as those sketched below. Also, Israel would have to overcome its reluctance, over the past two decades, to ratify the CWC.
Another part of the bargain would be concessions by Israel regarding its nuclear arsenal, which is cited by Syria as a key justification for its own stock of chemical weapons. Israel's elimination of its nuclear weapons is unlikely at present. However, there are less-stringent concessions that could make a CWC-focused bargain, as outlined here, tolerable to Iran, Egypt, and Syria.
(WARNING: Excessive Bull to follow) "...One concession could be for Israel to abandon its longstanding position of nuclear "opacity", acknowledging its possession of nuclear weapons and stating their purpose. Another concession could be a moratorium on Israel's production of fissile material. These concessions would enhance Israel's security, and could significantly improve the climate for an agreement that confirms Iran's status as a non-nuclear party to the NPT."