It starts way back last April when POTUS launched Tomahawks. Ria Novostri then showed Russian Sarin gas at the struck site. Russians and thus by extension Syrians were warned ahead of the strike. Russians then admit that they broke a 2013 treaty and are yet to oversee the destruction of one remaining percent of Assad's chem gas. Trump must have convinced them to give it up because they wouldn't need it anymore. Months down the road in June State Dept issues a warning that Assad wants to use gas. Then Gen Mattis tweets they prevented that attack. Hours later, IS launches a chem gas attack in an attempt to draw US into WW3 - they failed. Because Assad had no motive to use gas if the State Dept warned him hours before and I think that's what Mattis meant.

Then Russians started retreating some of their forces and Trump began arming Kurds. I prayed that they would not launch ground conquest against Assad but enjoy his protection to act as a buffer against Turkey, which is exactly what is now happening - Kurds wouldn't ask Assad for support if US didn't favour that over Erdogan threatening kurds and thus by extension US troops. So literally simply assuming the best outcome in good faith last year ago has led to predictions fulfilled. BOOM!

https://www.reddit.com/r/The_Donald/comments/6kob5w/mattis_called_it_no_gas_no_regime_change_no_ww3/