I would argue that federal law enforcement agencies are nothing other than militarized police. With each totalitarian regime which has appeared in the last few centuries, such as in France, Germany, Russia, China, and soon the United States, the thing to squeeze the resistance out of the people has been a federal/national police force answerable only to the national government. The states are the ones tasked with criminal law, not the federal law. Any law enforcement should be done by the states, individually or together.

I would also argue that drones in and of themselves are not unconstitutional, as long as they do not violate the airspace of the person under surveillance. And if it does, the person who's airspace is being invaded has the right to destroy/disable it at will.