Roberts wouldn't know his head from his a. In any case, the more Putin's troll factory feeds try to protect Trump through crazy mouth pieces like Roberts the more ordinary readers believe Russia has something to hide.
Chlorine gas munitions are all over Syria. A few shells were offloaded by whoever in an around the Afrin fighting . I recall sh#t loads of the stuff were unloaded on the Kurds in Sheikh Maqsoud …. again by whoever because normal command and control processes don't work very well in Syria.
Some of it may have been manufactured by ISIS and some chemical weapons of all descriptions were removed from Saddam's buried stockpiles by ISIS.
Back to basics though. Look towards North Eastern Iraq and a far worse risk exists. Should Khamenei missile and artillery strikes on targets in this area hit one uniformed US serviceman Trump will have what he needs. 4 horseman? Khamenei, Putin, Erdogan and Trump.
cheers