How effective are the U.S. drone strikes?

When Barack Obama was elected in 2008, his predecessor George W Bush's global 'war on terror' was renamed an 'overseas contingency operation'. But while the rhetoric has been less incendiary, far from abandoning the tactics of the Bush years, Obama has intensified the ferocity of attacks on the US' enemies. Under the command of the man who won the Nobel Peace Prize in 2009, the use of unmanned drone attacks has surged. And according to the Bureau of Investigative Journalism, so has the number of civilians killed. A New York Times article has revealed that the US president personally approves or vetoes each drone strike after consulting closely with security officials. There is no direct risk to American military personnel. But critics, including the Pakistani government, point out that the drone strikes are imprecise and violate the sovereignty of the countries they strike.