They are and they will continue to be, in one form or another. We need to start being smart about this.
@Sanguine PRECISELY! Nobody has EVER won a war by killing privates/illiterate ragheads,and we are not even fighting a war. We are fighting what everyone is calling an insurgency.
Which is actually irrelevant when it comes to defeating the enemy,regardless of what tag you place on the conflict. We live in an age of computers,and there is no shortage of VERY bright people who know how to hack into computer systems,or intelligence operatives who know how to track human targets.
The only REAL difference between ending an insurgency these days and winning a declared war is winning the insurgency is easier. ALL you have to do is two things.
1: Shut off the flow of money to the insurgents. When the insurgents are no longer getting paid,they will go back home. Even "true believers" need money to feed,clothe,and house their families.
2: Shut down their ammo and weapons supply lines. This is pretty much an automatic function of shutting down the flow of money going to them.
To do this you have to "discover" where the money is coming from,which is a joke because you can bet your bippy our government knows where the money is coming from,and probably already has the account numbers. You can do this several ways. The best is quietly approaching the bank managers and asking/telling them to name who the account owners are and where they are from,and then have them shut down those accounts and refuse to open new ones for the people who were accessing the accounts.
If that doesn't work,the next best step is "disappearing" the assholes running the accounts. You may have to "disappear" a few more bank managers before the word gets around that it is kinda dangerous to be laundering fundie Islam cash,but that is a small society where they all know each other,and it won't take long for them to notice some people have disappeared.
I would normally suggest after identifying the banks you would go to the leader of that nation and to the UN to have those accounts shut down,but we all know how laughable that is. Even if we said "Pretty please!"
Kill the leaders and the rank and file will all go back home. The few "true believers" that remain can be easily handled by the local or national cops once the leaders of that nation know we take it seriously.
Anytime in the future any radical shows up,play "whack a mole" before he gains much of a following.
To sum it up,the key to stopping this crap is to identify,locate,and neutralize the money men. Once the money stops flowing,everything else stops,too.