The pictures are horrifying.
Children and distressed parents choking and foaming at the mouth - in what's said to be the latest chemical weapons attack in Syria.
Donald Trump and other leaders accuse Syria's president of ordering the strike on rebel-held Idlib Province.
The Syrian army and its Russian ally are repeating their denials of chemical weapons use - they say government warplanes hit a rebel warehouse containing toxic gas.
All that just as western powers seemed to be coming around to the idea of allowing Bashar al Assad to stay in power.
So will policy change?
Presenter: Nick Clark
Guests: Joshua Landis, Center for Middle East Studies, University of Oklahoma.
Pavel Felgenhauer, Defence and Military Analyst.
Samir Al Taqi, Former Syrian government adviser.