&gt; Believe it or not the people pushing for surveillance are not villains out of a movie or TV show. They see a tragedy like Paris and they really believe that more surveillance would help prevent these kinds of things in the future.<p>Having the character genuinely believe that their harmful actions will serve the greater good is pretty much the most frequent advice to writing believable villains in any context, including for movies or TV shows.<p>&gt; Immediately after the tragedy is exactly the time we should be taking steps to prevent it in the future.<p>Immediately after the tragedy is when we should start taking steps to understand why it happened, and how (and at what costs) similar tragedies could be prevented. Jumping based on emotionally-driven haste into steps <i>intended</i> to prevent recurrence without due consideration is a great way to maximize the effect of the Law of Unintended Consequences, and to prove the adage about the paving material used in the road to perdition.