A significant part of the aftermath of an event is the so called “post mortem”: a thorough analysis of what went right, what wrong and why.
While “post-mortem” is a common practice within complex organizations and helps detecting flaws to be fixed or positive actions to be standardized, it must not be confused with the “rolling-barrell” attitude of putting the load of a (ex-post proven wrong) choice on somebody else’s shoulders.
As everybody outside the intelligence’s “inner circle” should, I neither claim to own the knowledge nor the expertise to assess the work’s quality and the assumed weakness of the French security system. But what I can say – relying upon my criminal trial lawyer experience – is that is always easier to find an explanation for something that happened once it happened, while it is very hard to “foresee” an event.
This is to say that once you know where to look for, the needle in the haystack is fairly easy to find. Or, put in other words, those who came late always look smarter than those who were there earlier: they already know where not to look at.
Whether the French intelligence services did a mistake or not, then, is of poor importance. Mistakes happens (much too) often and it wouldn’t be a surprise to discover that in the Charlie Hebdo massacre mistakes have been done.
But the best we can do is to learn from it, instead of publicly blaming people in the line of fire just for the sake of looking “smart”.