Back in 2006 the ghastly deaths of several men, women and children over the Atlantic Ocean were prevented when British officials foiled a plot to blow up as many as ten US – bound passenger jets with liquid explosives hidden in carry-on luggage. A U.S Congressman said that the subsequent arrest of some 24 suspects was represented progress in the fight against terrorism. Why then did a bullet dodged feel like the beginning of something and not the end? Since September 11, 2001, Americans have conditioned themselves to spike every triumph in the so-called war against terrorism with a shot of anxiety. They walk in the constant shadow of risk.The triumph against terror on Christmas Day was muted because it was also a test of our understanding of terrorism: should we react reflexively to every new terrorist scheme, regardless of the probability of the threat and the feasibility of preventing it?After the discovery of Umar Farouk Abdulmutallab’s terror plot, it seemed to make sense to respond by funneling money into the installation of full body scanners. In a world where successful anti-terrorism operations serve only to highlight vulnerability, stopping the next attack may seem an exercise in futility. But that’s exactly the point: terrorists will never be deterred forever. Like the old saying goes, “if at first you don’t succeed, try, try, try again” and try again they will. As such, it is worth considering the probability of an attack, rather than its possibility.Once terrorists decide to bomb an airline with explosives, how likely is it that they will succeed? Some 2,000 bombs are planted every year on U.S soil and almost none are liquid explosives. That’s because such bombs are extremely volatile. Every time a government scrambles to defend against the newest threat, it runs the risk of shortchanging more pressing ones. Investing in body-scanning machines or prohibiting carry-on luggage may provide a degree of security. However they do not take account of the fact that most of cargo shipped on passenger planes goes entirely uninspected, whether for bombs or anything else. Dealing effectively with the threat posed by al-Qaeda requires a more sober and rational approach than has been pursued over the past years, one that involves figuring out how much we are all truly willing to change our ways of life to reduce the risk of another 9/11.Until that calculation is made, terrorists will continue to succeed even when they fail.Author: Benjamin Adu-Boahene