The problem with the whole virtual fence thing is that to make it work, you have to have fairly massive and highly mobile ground assets immediately at hand as a reaction force. The functionality of the whole thing can be compromised completely by short-sheeting the reaction resources, which is a large part of the current problem with Bush's desire to help out his pals in Big Ag and other service industry fatcats in the Southwest. All it takes to render this system totally ineffective is either the Executive allocating the mobile resources badly (incompetently or on purpose) or for the Legislative to short-fund the response assets; it's attractive to both of them because either one therefore has the power to make sure it doesn't accomplish anything without the necessity of obtaining the other's cooperation.