Since I'm pledged to Aisling Duval, I can either interdict and kill ships pledged to any faction that is not part of the Empire within any of that faction's control systems, or I can take loads of Media Blitz Material to an opposing faction's control systems. If you click on a control system of an opposing power in the galaxy map with 'power play' selcted from the 'view' tab and then click the icon that looks like a bar graph (on the pop-up when you click on the system) you will be taken to a Power Play screen that tells you the current status of the system (fortify/undermine) and what the particular undermine task for that system would be. You can only undermine control systems of other powers. Depends on the ethos of the power you have pledged yourself to.
