… when two countries’ governments come to an agreement between themselves as to what a third country must do?
In the case of the US and Russia agreeing that the Assad regime must “place its chemical weapons under international control,” recent news reports indicate that the “international controllers” may include Hezbollah.
One of the main arguments for e.g. overthrowing Saddam Hussein was to prevent the acquisition of chemical weapons by non-state military organizations (usually they get referred to as “terrorist groups,” whether they are or aren’t). It looks like the Obama administration’s urge to intervene in Syria may have exactly the effect warned against.