Pulling out of Syria and concurrently announcing the withdrawal from Afghanistan were small actions with huge implications.
The precedent has been set.
Perhaps those announcements were intended to be five steps forward followed by four steps back, but one step forward remains-----few have realized he established the 'thin edge of the wedge'***, a not to be misunderstood 'shot across the bow'***?
Mattis got the message, FAST!!!!
***thin edge of the wedge A minor change that begins a major development, especially an undesirable one.
***A shot across the bow is an important technique for demonstrating that you are not to be messed with. In business and politics, it is necessary to be sure that you are staying on the offensive, rather than the defensive, to indicate a desire to compete and dominate.