I suspect their resources - boots on the ground if you wish - ready to be activated are rather limited even though the supply of potentials is very large. This attack apparently featured 9 people, that&#x27;s a relatively large number and it would not surprise me at all if that&#x27;s a substantial portion of the resources that they <i>could</i> activate right now. But given time new idiots will step up to fill the vacancy. Give it a few months or a year. Just long enough to get everybody to forget to be more watchful.<p>Sleeper cells are a very old concept. Go about your daily business and wait for a pre-arranged signal, go to a place, pick up instructions and weapons, do the deed. It could go from &#x27;innocent dude working in a bakery&#x27; to &#x27;hey, that&#x27;s my brother that blew up 20 people&#x27; in less than 48 hours.<p>And that&#x27;s precisely how they should do it if they wanted to stay under the radar. This recipe could be repeated just about forever without much chance of interference, and even that wouldn&#x27;t matter much as long as once every year or so a group would make it through.<p>The window in which one should catch a would-be terrorist is between 0 and 19 years of age, not in the last 2 days before they execute a plan. That is playing very bad odds.