To start off this discussion we have to make sure we are on the same page about what we are talking about. The good folks at MoveOn.org have put together a collection of Trump inciting violence.

I was thinking can’t Trump be charged with inciting violence? So, I looked into it and the answer surprised me. No, but he is getting close. His speech must be proven to have intent to cause violence, there must be the proven likelihood of violence and the imminence of violence. In 1919 The supreme court made it illegal to yell fire in a crowded theater and in 1969 the supreme court ruled that the speech must be tailored to invoke a violent reaction and Trumps flippant remarks don’t qualify. Take for example that YouTube video the Innocence of Muslims likelihood and imminence could be proven but intent is harder to prove and the actors were misled about the contents of the finished film.
Trumps speech is deplorable and ugly  but his remarks seem off the cuff. Reactions to situations happening right then, so he is still protected under the first amendment. He also is close but not guilty of hate speech, because, his calls for violence have been to remove protestors from his rallies.  He has thrown out minorities who were not protesting he did not call for them to be harmed. I think he will slip up and cross the line soon and his lawyers will be ready I’m sure but at least he will be stuck paying the legal fees of the followers of his that are violent towards others.