Consider the freedom-loving town of Deer Trail, Colo., which could soon pass an ordinance offering drone-hunting licenses and a $100 bounty to anyone who shoots one down, despite such groundings being otherwise illegal. So far, 12 states and several dozen U. S. cities have introduced legislation limiting unmanned aerial-vehicle (UAV) applications in their skies.

The benefits of UAVs are well known. But UAV applications raise ethical questions about how to resolve conflicting goals, such as ensuring national security while adhering to international law. For example, U. S. UAVs have made hundreds of strikes to kill enemies and destroy targets in six foreign countries over the last decade, but some of the strikes may have violated international rules that say military force is only legal for self-defense, with the invaded country’s permission, or with U. N. clearance. For this reason, groups including the International Committee for Robot Arms Control oppose all automated military forces, including UAVs.

Even nonmilitary drones face significant opposition, mostly from groups such as the Electronic Frontier Foundation trying to protect Fourth Amendment rights “to be secure in persons, houses, papers, and effects against unreasonable searches and seizures.” The International Association of Chiefs of Police (IACP), which steers law-enforcement policies, recommends the use of UAVs for police surveillance but opposes equipping UAVs with weapons, citing limited safeguards in current technology to avert tragic mistakes. The American Civil Liberties Union (which sued Defense Secretary Leon Panetta and others for drone strikes that killed Americans in 2011) applauds the IACP recommendation.

In any case, a new federal law makes it easier than ever for police departments and emergency-response agencies to buy drones and get permits to fly them. The Federal Aviation Administration has already received dozens of permit applications and recently published a report on how it will handle new drone traffic in U. S. skies.

Few in the engineering community have made recommendations about proper UAV use, and ethics codes offer little concrete guidance. Consider that of the Society of Professional Engineers: “Engineering … impacts the quality of life for all people [so] services provided by engineers … must be dedicated to the protection of public health, safety, and welfare.” This implies that even UAV engineers not legally responsible for the ramifications of drone use could bear complicated ethical burdens. But let’s face it, no profession effectively self-monitors their industries.

The Ethics + Emerging Sciences Group of California Polytechnic State University aims to buck that trend. A few years ago, it conducted a study for the Office of Naval Research that summarizes the moral dilemmas that arise when using autonomous military robotics (while acknowledging the need to “leverage the benefits of technology.”) The group also published a book last year with MIT Press that outlines pragmatic approaches to answering UAV-related ethical questions.