As I just said on another thread.
Trump boasted what he was definitely going to do, but did not go ahead and do, and meanwhile Russia, Assad and Iran are preparing, and chuckling “Thanks Trump for the heads up”.
Mattis is watching all of this unfold and receiving updates on movement. Its making both Russia and Syria squirm, which is good.
No one has a clue what Trump is going to do regardless of what he tweets. Mattis may not even know yet