Hacking the Grid?

This morning we are featuring on ControlGlobal.com an article from Red Herring about the potential for hacking on the power grid. The article points out the usual stories about the plants that have been hacked, or had virus trouble, and quotes some people who know what they are talking about, like SecureSystems Insider columnist Dale Peterson from Digital Bond. Here's my problem with this. In the very early 1970s, some of my friends were leftist radicals (junior Weathermen, and so on) and they would always be talking about bringing down the grid to stop the Vietnam War. As we all know, it never went down. Because of my peculiar cast of mind, I decided to see what it would take to do it, since all these "parlor pinks" were satisfied with talking about it. I figured out several ways that a dedicated group of less than 20 terrorists could do it. Now, I am not the brightest bulb in the box. If I could figure it out, so could my friends in the 70s, or al Qaeda in the 90s or today. Red Herring's articles note that in Afghanistan, plans to disrupt the grid in the United States were recovered from al Qaeda computers. So why then hasn't it been done? There are lots of groups, both here and abroad, with agendas that would lend themselves to that activity. Maybe the reason is that it isn't that easy after all. What do you think? Walt