Honestly I think the more likely thing is an increase in "lone wolf" incidents. The name is a misnomer, though. While they act alone, they are interconnected via dark corners of the internet where they share "manifestos" and ideas about targets and tactics.

All the more reason for people in leadership positions, and candidates for office (and yes, I am just addressing myself to the GOP as there is no parallel on the left) need to stop pouring gasoline on the fire and stop playing with matches.