humanitarian law."UN report calls for independent investigations of drone attacks ". The Guardian. 18 October 2013. Additional concerns For drone strikes to be effective, the United States must obtain consent from the host country they are operating in. The growing chorus of objections from host countries, most notably emanating from Pakistan, seriously inhibits drones' effectiveness. "Host states have grown frustrated with U.S. drone policy, while opposition by non-host partners could impose additional restrictions on the use of drones. Reforming U.S. drone strike policies can do much to allay concerns internationally by ensuring that targeted killings are defensible under international legal regimes that the United States itself helped establish and by allowing U.S. officials to openly address concerns and counter misinformation." Micah Zenko at the Council on Foreign Relations believes the United States should "end so-called signature strikes, which target unidentified militants based on their behavior patterns and personal networks, and limit targeted killings to a small number of specific terrorists with transnational ambitions. He wants more congressional oversight of drone strikes and stricter regulation on armed drone sales. Finally, he recommends the United States work with international partners to establish rules and norms governing the use of drones. Zenko believes the U.S. government has not been transparent regarding how non-battlefield drone strikes are reconciled with broader foreign policy objectives, the scope of legitimate targets, and their legal framework. While drones may be a critical counterterrorism tool that advances U.S. interests, their "lack of transparency threatens to limit U.S. freedom of action and risks proliferation of armed drone technology without the requisite normative framework." Zenko thinks current drone policy might share the same fate of the Bush-era enhanced interrogation techniques and warrantless wiretapping, both of which were unpopular, illegal and ultimately ended. Harvard Law School Professors Gabriella Blum and Philip Heymann cite six potential hazards of targeted killings: First, the so-called Hydra effect, or the rise of more—and more resolute—leaders to replace those who were recently "decapitated." Second, drones can drive terrorist leaders into hiding, making the monitoring of their movements, and subsequent intelligence gathering, extremely difficult. Third, "the political message flowing from the use of targeted killings may be harmful to the attacking country’s interest, as it emphasizes the disparity in power between the parties and reinforces popular support for the terrorists, who are seen as a David fighting Goliath." Fourth, when conducted in a foreign country, drone strikes run