From the thesis abstract: "The United States has increasingly relied on targeted killing as an important tactic in its war on terror, and will continue to do so for the foreseeable future. Despite its increased use, targeted killing has proved a divisive practice and generated considerable controversy. Many criticized the lethal targeting of a U.S. citizen in 2011 as violative of U.S. law and a deprivation of due process. Still, international and domestic law appear to support the government's ability to lethally target U.S. citizens. To date, however, the government has demonstrated little transparency and no public accountability regarding this contentious and sensitive practice. While some degree of secrecy is warranted, the government must be more forthcoming if it wants to maintain the viability of an increasingly important tactic in the war on terror, especially where the targeting of U.S. citizens is involved."
Defense Technical Information Center (DTIC): http://www.dtic.mil/dtic/