David Horowitz, an ex-Marxist, is an important person to listen to because he knows the strategy of the communists during the 1960's. It's important to learn from our history, so we are not bound to repeat it.
I recommend watching this video of him speaking here, to understand the depth of the issues at hand,
http://www.c-span.org/video/?191779-1/book-discussion-professors-101-dangerous-academics-america
In that light, I would also recommend watching this, which happened not too far from my home here in California.
http://youtu.be/zuNva3j12X0
I hope everyone is listening to that woman speak. These people are crazy and do want to wipe out people who disagree. This is happening across this country! Look at some of the other more recent speeches that Horowitz gave from his book tour,
http://youtu.be/Tbi99cT7bAU
It takes time to watch all these videos, I know, but you will start to get the depth of the problem. The solution is simple, we need to remember our history, and stand up for what we believe in. I've never been a fan of Glenn Beck persay, but I recommend this video to everyone.
http://youtu.be/H8zz_mBb80U
