I know there are very specific laws related to making threats against the President ... I am not sure what laws exist related to making threats to someone under Secret Service protection, but at the very least it is something they have to take seriously.
Considering Glenn Beck just happens to be at CPAC - a place that up until an hour ago Trump was planning to attend - I’d say that it is pretty serious.
He is inciting and he knows perfectly well the dog whistle he is blowing.