Here (German) is an excellent text, advocating sobriety in the face of terrorism, if it were at all possible. The sobriety advocated is of a rational kind, seeing that the risk of being the victim of a terrorist act is much smaller than that of being involved in a traffic accident for instance. However, sobriety must not become indolence towards victims, once the inevitable happened. And yet, the repeat use of the subjunctive indicates the author's awareness of the danger involved in that approach: cynicism.
What can we do in the face of the terrorist threat? The political response by the authorities is one thing of course, althought the strategies chosen are open to debate, and must remain so by all means. Seeing that the new breed of terrorism is perpetrated by loosely, maybe even only ideologically connected cells instead of a hierarchical organisation with a command & control infrastructure that can be destroyed, I wonder whether there is a proportionate citizen response that is not subject to the dangers of vigilantism. I suppose vigilance & loyalty towards open societies may have a particularly appropriate place for instance in immigrant groups where fundamentalism & extremism can thrive if unchecked. For the rest, it is trying to remain sober, of course, and engaging those in debate who mistakenly think that terrorism is the weapon of the weak against the strong - it is the rage of the angry against the defenceless and innocent. "It is an evil means to an evil end." (Sir Jonathan Sacks)