It seems to me that if someone is really crazy enough to shoot somebody else out of rage or any other mental disorder they want easy, unarmed targets that will be at a target rich enviroment such as a school, college, mall, etc. Shooting a politician still isn't easy, and often with security these days takes too much planning, and the shot that some might have to take would take a reasonable amount of skill. Most crazies just want to get it over with and not go through all of the preparation and planning.
It's pretty apparent from past threads that many on hear think that shooting efficiently is just pointing and pulling the trigger...not so. Just my .02.