Peters puts it in better terms than I have ever been able to. The whole point of the terrorist/insurgent/patriot/dirty rottesn SOBs is to get the home front to capitulate. If you want metrics to measure success, the opinion polls show that they are succeeding in their objectives.
On a side note, I met Peters during Desrt Storm. He was on special attachment to the General Staff, because of whatever book he had just written. Like most tankers, he was on the small side, big guys tend to have less time to react to the bump and grind that goes with cross country travel in a 70 ton taxi. I found it odd though, that he was not a very impressive charachter. Seems it is easier to create heroes in fiction than make real people seem that way.