The Washington Post has a story this evening on an often-overlooked aspect of interagency cooperation in connection with both combat operations and counterterrorism: FBI agents deploying into the field with JSOC units.
Most of the story focuses on such deployments in the context of combat zones (Iraq & Afghanistan), with an emphasis on the extent to which the military came to place great value on FBI expertise in sensitive-site exploitation and interrogation. That much is not particularly surprising of course, even if we don't hear the details often. What's interesting about the story is not that it depicts FBI agents going downrange, nor even that it depicts them coming along on raids (the sensitive-site exploitation mission, after all, implies that the agents would at least be close-by during raids). Rather, the interesting part is the fact that the agents frequently participated directly in firefights as the raids unfolded, and this eventually generated significant internal debates regarding whether this role was proper. The story does not provide much detail as to the precise terms of that debate, alas. Speculation: these were mostly if not entirely capture-oriented operations, in which the involvement of the FBI agents in resulting firefights was justified on escalation-of-force grounds.