To the extent the local law enforcement’s lack of protection endangers the speaker and his audience, the FBI should be involved.
Better yet, state law enforcement authorities.
Anybody intending to attend, should sue for violation of their free speech rights, as should the invited guest speaker.
The left will only stop,, when made to feel the sharp bite of the law.
Harvard Prof Cornel West- Behind Violent Berkeley Protests ?
http://www.freerepublic.com/focus/f-bloggers/3521070/posts