[s_q_b]

This is exactly spot-on.

My only addition would be that the rebel groups must be inspected to determine whether they have gained control of any chemical stockpiles.

[rdl]

Definitely -- all chemical weapons should be escrowed. I'd be ok with doing a 1 for 1 swap of chemical for conventional weapons in exchange, if required, if the goal is just to get rid of the chemical weapons.

[s_q_b]

Exactly. That's smart foreign policy. A limited definable goal, preservation of the norm of prohibition against the use of chemical weapons, and a way to accomplish it that respects the interests of each of the parties.