president donald trumump has decided to fast track the departure of his secretary of defense.im mattis intended to stay on through february to take part in a planned nato meeting, but trump moved the timing up to january 1, effectively firing him after he quit. mattis is reportedly leaving over the president's decision to withdraw troops from syria. the order from that -- the order for that retreat has now been signed. the order has been approved after the shock resignation of jim mattis. he announced he would resign after the president's decision to withdraw troops from syria, a decision not welcomed by president trump. he is being forced to leave his post early with patrick shanahan taking over the post on the first of january. shanahan will give up his role as the pentagon's 33rd deputy for the position. he has limited background in foreign policy. president trump took to twitter to defend his stance. >> i just had a long and productive call with president .rdogan of turkey we discussed the highly coordinated pullout of troops from the area. after many years, they are comin