Funny how fast that plan came together, innit?
Giving O and P the benefit the doubt here...
What if they were playing "good cop and bad cop" with Syria with O being the "bad cop". Think about it, we already have a history of going into countries and breaking their stuff, so Assad had to know there was at least some chance of it happening again. That was the stick. Russia, after starting off with a strong objection, the slowly softening, comes up with a plan that gets rid of the weapons, but keeps Assad from being attacked. At that point, it has to seem like a great idea.
Do you think Assad would have agreed to the Russian initiative at the start of all this? I don't. A risky ploy, but if intentional, it worked quite well.
If not intentional, well, we got lucky.
Chris