I agree that we need to keep our eyes open. But the 5000 number is dominated my sympathetic hangers-on who are only able to provide shelter and support for the people who could actually do us harm. I'd guess that 95 percent of these morons wouldn't know a cell if it was stuck in their ear. I bet there are less than 200 that could play even a small role in simple mission to destroy something, and much less than that who could take an significant role, like the 19 of 9/11.
These people are scared and lost, but are still dangerous until their funding disappears and their organizations suffer further defeat. Our agencies are watching these people and learning, and one reason they're still here is that we want to see more.
I nonconcur with this analysis. The sympathetic hangers-on will be ten times that number. And I believe you will find them in every mosque.
These guys are prepared to get killed (like the LAX shooter), what the heck do they care about the 1% chance the FBI is tailing them? Compared to a planned suicide mass murder, what makes you think they are "scared and lost" by the minimal threat of being watched by a totally undermanned and overwhelmed FBI?
Do you think they worry about deportation or a Gitmo vacation when they are already planning suicide murder?