Right now, we are like a yippy little dog. At the slightest provocation from terrorists, we run around chasing our tails. It doesn't matter if the terrorists are really planning an attack or not, they just have to hint at it and we warn the public, stage the police, close down sections of town, and detain anyone who looks arabic or has a camera.
Each time there is a reported threat, but nothing happens the credibility of our leaders goes down. No arrests, no attack, nothing but some civil liberties violated and a lot of inconveniences. And when we find out that, like with the latest alert escalation, the information they are acting on is years old and actually predates 9/11, is further hurts the credibility of our leaders.
This also let's the terrorists know what channels of information have been compromised, there by helping them strengthen their information network.
So, in the end the people let down their guard, as they are tired of our government crying wolf, and they have tighter and more secure communications.
This makes me feel the current alert system is flawed. I don't know if a more subversive system of infiltration and old fashioned spying is the answer, but I do feel that us jumping at every squeak will not be able to last for long.