The sad reality is that not only can the attack we saw in Paris, France happen here; they already have. A lot of digital ink has already been used discussing the event and how to deal with one should it happen to you. Greg Ellifritz of Active Response Training has an excellent analysis on the incident and potential responses to future events that I highly recommend everyone read. I would like to add that when the attackers are armed with a weapon designed to take out a tank (RPG) most building security will be worthless even if they can’t find someone to open the door.
How to prepare for/prevent/limit the carnage of such attacks is not an easy question to answer. The events after the Boston Marathon bombing show that a small group can be just as effective here as they were in Paris. Encountering the Police as an armed citizen in the aftermath of an attack has its own risks, but may be unavoidable. This means you will have to figure out how to ensure you are not seen as a threat.
As Brandon writes gun control will not save you. France already had gun controls in place that would make your average American anti-rights activist soil themselves in joy. On the other hand Interpol echos a sentiment expressed a long time ago that arming the good guys is the best and lowest cost answer to the growing threat of these kinds of attacks.
One thing I haven’t seen yet is a call for training in how to deal with traumatic injury. Yes, stopping the bad guys is important but shouldn’t we also be trying to save the lives of their victims who are injured? Consider taking a course in traumatic injury response and obtaining a small traumatic care kit for carrying every day. If not your life it may save some one elses.