"Simply, because, you see the useful idiots; the leftists who are idealistically believing in the beauty of Soviet or Communist or Socialist or whatever system; when they get disillusioned, they become the worst enemies. That's why my KGB instructors specifically made the point, "never bother with leftists, forget about these political prostitutes - aim higher" this was my instruction"

---Yuri Bezmenov, KGB Defector
http://www.freerepublic.com/focus/f-news/2095202/posts