Domestic Law Enforcement by Drones

When is it acceptable to use the military, or military-grade {weapons, equipment, training, hardware, etc.} domestically? Is there legal due-process in place to ensure that assassinating American citizens in America [who are a clear and present danger] is not a step onto a slippery slope towards cowing our own populace with drone warfare?

 

RE:

 

From comments:

One MAJOR point being left out of those headlines are that there are not armed drones….they are not the “predator” versions the news always shows bristling with missiles.

They are surveillance drones, and if used in a man-hunt, how are they any different than a bunch of guys flying around in helicopters doing the same thing?

— anonymous

 

True, the ones in use right now in this case are not armed, but I think that makes “now” all the more important a time to ask the question in case we as a public wish to decide that the correct answer should be “never”, just like it is basically never okay for the state to use main battle tanks for the purpose of law enforcement.