That’s the proper and permanent solution but imagine the weeping and wailing that would follow. The same solution would solve the border problem kill a few thousand they will stop coming.
Then the defense establishment should simply invent a story about Isis version 2.0 that wants to kill off all prior members of Isis. Ultimately, very few care about several hundred people being killed over there in that part of the world. Like it or not. Get it done, I say.