What consequences should Gary face?
Firstly, he would be involved on murder. That's not a great experience to have, for most people.
He would at least be on trial. I don't exactly know how incitement to murder is treated in the US.
It could even be considered domestic terrorism (an assassination made to intimidate a group based on an ideological agenda/government policy). Then, I don't know what would happen, exactly. The FBI would probably get involved?