There’s a precedent for the symbiotic relationship between Trump and his protesters. Here’s a description of ritualized violence at the rallies of the English Fascist Oswald Mosley in the 1930s:
Violence was implicit in every aspect of the movement from the day of its foundation. Apart from the para-military character of the whole organization, the system on which meetings were run was deliberately provocative. The speaker would arrive in uniform accompanied by a uniformed escort. As he mounted the rostrum his escort would greet him with the Fascist salute and then form up in front of him, facing the audience, and assume a truculent attitude. The speaker would then warn his audience that any attempt to disrupt the meeting would be met by force, and frequently it was. This technique reached its height at one of Mosley’s biggest demonstrations at Olympia. 15,000 tickets were sold, mostly through the theatre ticket booking agencies, with considerable publicity engineered through the Daily Mail and the rest of the Rothermere press. A phalanx of uniformed Fascists filled the steps of the main entrance and the hallway, checking tickets and frisking suspected members of the public. The aisles of the hall were lined with other members, whose function soon became apparent. Mosley appeared to a fanfare of trumpets and started to make his speech. Before he had completed his first sentence someone in the audience got up and shouted a protest. Mosley immediately stopped speaking, a spotlight picked up the offender in the darkened hall, and a body of stewards ran in, beat him up and carried him outside. This process continued for more than two hours. Outside the hall there was an opposition meeting of 100,000 protestors, with a force of 700 foot and mounted policemen attempting to keep the two factions apart. The atmosphere became increasingly tense as the interrupters were ejected: many of them showing clearly the injuries which they had suffered. The whole affair was not finally over before the early hours of the morning.
The description comes from Jason Gurney’s memoir Crusade in Spain (Faber, 1974).