The Return of the Radicals

As I finished my previous post, I got to thinking; how close are we to a return to the violent radical groups that existed throughout the late 60's and early 70's?

We've seen serious violent events from groups such as the Animal Liberation Front and their comrades at the Earth Liberation Front as well some communist elements, but we've seen nothing like the crimes perpetrated by the Weather Underground, the Symbionese Liberation Army and others.

How far are we from the point that a leftist group, created to protest the war in Iraq (and Afghanistan) goes from peaceful (mostly) protest to outright terrorism?

With groups such as International A.N.S.W.E.R and Moveon.org (update: or who read Ted Rall) recruiting members and filling them full of crazy left-wing rhetoric, how long before one of those recruits takes the lesson to its logical conclusion?

It's not hard to envision a young adult who attends an anti-war rally, a rally perhaps where he is surrounded by signs that equate Bush and Hitler or that advocate the terrorist elements of radical Palestinians growing hateful. How much of a stretch is it to see that same kid deciding to follow up on the rhetoric and take action?

Update: Terri has some thoughts as well.