Surprisingly little, for one reason in particular: Neither he nor anyone on his team has an iota of grace or restraint.
The people saying this is a game-changer event for the GOP campaign assume they'll be able to capitalize on it, but they'll drive it into the ground in very short order. I mean, the FIRST THING 45 should have done was to visit, or at least address the family of the attendee who died & acknowledge their loss but, being a selfish oaf, he can't.