The Milgram experiment showed that ordinary people would generally follow the rules of engagement given by an authority. This moves the moral choice from the individual to the creator(s) of the ROEs. Such has always been the case, since at least the time when officers were able to remove themselves from personal risk while ordering death by others. Drones don't change that.
Others might point to the Zimbardo-Stanford Prison experiments where ordinary college students, placed in an environment where inhumane behavior was allowed without sanction, would behave inhumanely. Applying this to drone strikes assumes the command chain would allow the drone operator (newspeak there, executioner might be more apt) freedom to expand the rules of engagement beyond their original scope.
I, rather, would point to an alternate reference which has been repeatedly shown more authoritative and accurate than any psychological or sociological study in the last 50 years. That would be Star Trek, the Original Series. In the Episode Mirror-mirror an unfortunate transporter accident caused Captain Kirk to be transferred to a bizarro parallel universe where good and evil were swapped. At the same time, his evil twin, the Kirk from that place was swapped into the ecumenical, diverse, kum-ba-yah Enterprise in our space. When in his own ship, the 'bad' Kirk has access to a button controlling an alien technology which allows him to remotely eliminate (no blood, this was prime time in the '60s) his competition. The script authors proved that our Kirk, the 'good' Kirk was in fact good by giving him opportunity to use that magic button and having him decline.
Applying all this to drones; the simplicity of pushing a button to violently eliminate the 'bad' guy on the other side of the world is too tempting to give to anyone, particularly politicians. There is a constellation of conditions which grease the slides to misuse: separation from events on the ground, lack of personal risk, self delusion, rationalization and indoctrinated hatred make declining to push the 'bad' Kirk's button less and less likely.
Others might point to the Zimbardo-Stanford Prison experiments where ordinary college students, placed in an environment where inhumane behavior was allowed without sanction, would behave inhumanely. Applying this to drone strikes assumes the command chain would allow the drone operator (newspeak there, executioner might be more apt) freedom to expand the rules of engagement beyond their original scope.
I, rather, would point to an alternate reference which has been repeatedly shown more authoritative and accurate than any psychological or sociological study in the last 50 years. That would be Star Trek, the Original Series. In the Episode Mirror-mirror an unfortunate transporter accident caused Captain Kirk to be transferred to a bizarro parallel universe where good and evil were swapped. At the same time, his evil twin, the Kirk from that place was swapped into the ecumenical, diverse, kum-ba-yah Enterprise in our space. When in his own ship, the 'bad' Kirk has access to a button controlling an alien technology which allows him to remotely eliminate (no blood, this was prime time in the '60s) his competition. The script authors proved that our Kirk, the 'good' Kirk was in fact good by giving him opportunity to use that magic button and having him decline.
Applying all this to drones; the simplicity of pushing a button to violently eliminate the 'bad' guy on the other side of the world is too tempting to give to anyone, particularly politicians. There is a constellation of conditions which grease the slides to misuse: separation from events on the ground, lack of personal risk, self delusion, rationalization and indoctrinated hatred make declining to push the 'bad' Kirk's button less and less likely.
So how, exactly, does God know that She's NOT a brain in a vat? 
