No need to watch the entire video clip. The first thirty seconds are enough
One narrative holds that we, elements within the US, created ISIS when we armed "moderate factions" in Iraq and Syria with arms freed from Libya during the (US sponsored) Arab Spring. Those "moderate factions" either turned the arms over to less moderate factions or radicalized once they had the means to exterminate their neighbors.
Intervention in Syria was then sold on the basis of the genocide of Yazidis and Christians. That morphed into unseating Bushar al-Assad the current ruler of Syria.
Trump recently announced the US will withdraw forces from Syria, all 2500 of them.
Mattis, one of the good guys, resigned presumably in protest.
Syria is former President Obama's and Mrs Clinton's war. The original objectives, as stated, were acheived. ISIS is not extinct but they are no longer strong enough to commit genocide.
I share concerns that the fire is not out and might erupt again but must balance that against the need to slow down our military's operating tempo. We are over-extended.
Further, we don't need to be provoking Russia. There is no profit in it for most Americans. Assad might not be sweet and cuddly but we saw Iraq explode when we knocked out Hussein.
The operational tempo plays even more into the decision to exit Afghanistan. Launching F-18 from aircraft carriers in the Indian Ocean to support fighters on the ground in Afghanistan has very low pay-off for the investment. The loiter time is short and it pounds the snot out of the equipment...the hours add up quickly.
As equipment wears out there are two choices: Don't support the guys on the ground or pull the guys on the ground out of theater.
If we arm wrestle with China we will be at a disadvantage if we are over committed in Central Asia and the Middle East. China will see pull-outs as our preparing for a potential, future conflict.
China respects strength. I am reminded of a story a fellow parent told me. He was frustrated that his kids would not mind when he told them to do something. Then, just as he was about to physically enforce his will, the kids would magically mind.
Having an inquisitive mind, he started experimenting to see what cue the kids were homing in on. It was when he gripped the arms of chair prior to getting out of it. Then it became easy. He would give the command, "Susie, stop throttling your little brother." and if she did not comply in five seconds he would grip the ends of the arms of the chair as if preparing to launch...and Susie would let go of Biff.
From a timing standpoint, if Trump planned on pulling troops out of Iraq and Syria, this is a good time. He is getting monkey-hammered due to the stock market sliding. Might as well take all the medicine as early as possible. People have eighteen months to forget.
And this may simply be a distraction on Trump's part. Who knows what his over-arching goals are? Trump is a master of tacking into headwinds, not tact in the face of opposition.
Mattis has been there two years, roughly. Trump is rough on his cabinet.
The other phenomena to consider is the Bridge over the River Kwai effect. Results oriented people can hyper-focus on the immediate task and lose context. Mattis is results oriented.