I believe it was more than once because I remember other threads not that long ago about Trump wanting to “punch someone in the face” and another time about offering to pay for the legal defense of anyone who “beat the crap out” of his disputers.
I’m pretty sure it was once at one event many weeks ago. I’ve watched almost all of Trumps rallies on YouTube. Original sources are always best if you want the truth.
The news media and social media are fueling the fire more than any one candidate.
Now, picture yourself there for a minute, and just say (for instance) that you had your wife and kids there, and some nutball protester started flailing around punching everyone there, including your wife and kids. Would it be appropriate for you to use necessary force to stop him from hitting them, and discourage him from trying it again, including possibly punching him in the nose?
Watch this clip for yourself, so you can see the context of that Trump comment, which was fully justified, and did not play a part in BLM's decision to try to disrupt his speech. (BLM has also disrupted a Bernie Sanders rally, and a Hillary Clinton rally, and neither of them had said anything about punching anyone in the face in any of their speeches.)
Here, watch the clip:
Donald Trump on protester (who was crazily flailing about, violent punching random people in the crowd) - 'I'd like to punch him in the face'