I disagree he would never order it. I think he would stir up his base into a frenzy so that one of them would do it. Look at how he stirred violence at his rallies. His comments endangering Katie Tur and others.
His last rally his comments about Mueller were awful. His tweets about congress. All to stir the base.
His driving support is based on cult of personality not so much on ideology. Cult of personality has often in our history lead to murder. Jim Jones and Charles Manson are two.
If you recall every act of violence or threat of violence in his name Trump took zero responsibility.
If Trump does build his followers to a violent frenzy he will take zero responsibility.Something he cannot do if he orders it directly.