The US has been using armed drones in the 'War on Terror' since the year 2001. Though they are used in targeted killing, civilian casualties cannot be prevented. This raises legal and ethical questions. A conceivable scenario: a truck approaches a village near the Pakistani-Afghan border.
At the village, the weekly market is being held, attracting people from the entire region. Two men are sitting in the truck. Secret service experts at the American command central affirm that the men are Taliban fighters and that they are carrying a couple hundred kilograms of explosives on their truck. Information from satellite pictures, contacts on the ground, routine movement patterns and pictures taken by the Predator drone circling overhead all conclude that the truck is a moving bomb. It is supposed to explode very soon at the market.
There is only one way to stop the bloodbath: to fire the drone's Hellfire rockets at the truck. Deadly cost-benefit calculation US drones might soon join French fighter jets in Mali Between June 2004 and September 2012, employees of the American Central Intelligence Agency (CIA) and the US military opted for a drone attack 344 times - 52 times under President Bush and 292 times under President Barack Obama.
The decision is based on a seemingly straight forward cost-benefit calculation: The death of two Taliban insurgents is weighed against the possible death of dozens of civilians in a terrorist attack. Yet the situations are nearly as never cut and dry as the scenario described above.
It is difficult to determine whether or not the drone attack will take civilian lives. Up to September 2012, between 2,562 and 3,325 people were killed in Pakistan alone in drone attacks. The Bureau for Investigative Journalism, an NGO, estimates that there were between 474 - 881 civilian casualties in those attacks. The large variation in the estimate is due to the fact that US government does not comment on drone attacks. The NGO has to rely on media reports and eyewitness accounts for information.