a few words on terrorists
Terrorists are not supermen. They are generally vastly outgunned by the security forces of whatever country the are operating in - in fact, they usually could not stand up to an infantry section. This forces terrorist groups into several compromises:
1) Because they cannot stand and fight, they are forced to seek surprise as a precondition to attack;
2) In order to achieve surprise, they have to learn everything they can about the habits of their target; and
3) To learn everything they can about their target, they have to get close enough to see them, and for a long enough period of time to gather meaningful information.
Herein lies their weakness, and an opportunity for antiterrorism planners. This is why we observe, and why we use random antiterrorism measures.
A terrorist movement looks like a pyramid. The base of the pyramid is the ideological support - the largest group, willing to support the cause, but unwilling to go to jail. The next (smaller) level up is the terrorist support layer - people willing to help through fundraising, carrying equipment, etc, but not willing to commit violence. The next (smaller) level yet is the active cadre - the terrorists willing to kill people and train other terrorists. The top of the pyramid is occupied by the committed leadership - those psychopaths willing to murder the innocent and spend the lives of those below them.
The line between ideological support and active support is the legal/illegal cutoff line. Those below the line limit their involvement to illegal acts. The goal of antiterrorism legislation, such as the USA PATRIOT act, the UK's Prevention of Terrorism Act, and the now-defunct Canadian War Measures Act, is to
grant the state temporary powers to lower the legal/illegal cutoff line, allowing counterterrorism forces to arrest the persons occupying the bottom of the pyramid. We already know that they do not want to go to jail, so they are easier to turn. Information that they can provide to investigators is used to trace the membership up the pyramid, hopefully ending with the arrest or killing of active cadre or committed leadership.
Liberal democracies don't usually allow this state of suspended liberties to go on for long for fear of risking the terrorists achieving a victory by forcing society to change for good.
As terrorism is usually a full time job, terrorists require the support of those less ideologically committed than they are. Capture and interrogation of the support element can lead to the destruction of those personnel higher on the pyramid.
As we have discussed earlier, destroying terrorists is the role of government.
The role of the security profession is to protect our employers and their assets, and to support counterterrorism forces wherever possible. The best way to support CT forces is to ensure that our own facilities are hard targets and by reporting suspicious incidents to them quickly and accurately. This reporting will allow them to identify members of the support and active cadre early, disrupt their actions, and eventually capture their leadership.