According to the CIA, the Soviet Union had an extensive program to provide its third-world proxies with an array of chemical weapons and train them in offensive chemical warfare, often conducting the attacks themselves. 
In Vietnam, Laos, and Cambodia, thousands (a very conservative estimate) were massacred in hundreds of chemical weapons attacks carried out by the North Vietnamese, the Soviets, and their proxies.
In Afghanistan, the USSR gave chemical weapons to the communist regime and its advisers oversaw their employment against unruly areas at least seven months before the Soviet invasion. After the invasion, the Soviets conducted hundreds of chemical weapons attacks in Afghanistan.
And why did the Soviets do this? Because chemical weapons are demonstrably effective against insurgency. Suck on that, Assadists.
cc @JettGoldsmith @OzKaterji
cc @JettGoldsmith @OzKaterji
A core part of Soviet support for Egypt's military, especially its invasion of Yemen, was chemical warfare, which Soviet technicians and soldiers oversaw.
The idea that Russia is not actively involved in Assad's chemical weapons attacks is laughable. Why would Syria suddenly be different than any other client regime the Russians have trained to use chemical weapons [and overseen their use] as an integral part of military strategy?
And if you want to know whether anything has changed, ever, here are excerpts from a 1980s CIA report on why the Russians feel like they and their clients can can employ chemical warfare with overall impunity
Certainly the Europeans haven't changed at all. Conspiratorial suspicion of the US, weakness, desire for close relations with the Soviets and mutual economic interests...
And here the CIA hits the nail on the head about why perceptions (of the reality of) Western disunity is fatal when it comes to deterring Russia and its clients.
It should be noted that certain allegations of USSR/proxy CW use are controversial, some going so far as to say fabricated. The US has never backed off its convictions. For a variety of reasons, we'll never know "for certain." pdfs.semanticscholar.org/d664/e8c352d6c…
