The background and pro and con arguments were written by ProCon.org staff based upon input from the following footnotes (directly referenced) and sources (used for general research and not directly referenced):
Footnotes:
  1. Brett Holman, "The First Air Bomb: Venice, 15 July 1849," airminded.org, Aug. 22, 2009

  2. Pew Research Center, "Global Attitudes Project," pewglobal.org, July 18, 2013

  3. John Sifton, "A Brief History of Drones," thenation.com, Feb. 7, 2012

  4. Joakim Kasper Oestergaard, "About the Predator and Reaper," bga-aeroweb.com, Dec. 2, 2013

  5. Ritka Singh, "A Meta-Study of Drone Strike Casualties," lawfareblog.com, July 22, 2013

  6. The Bureau of Investigative Journalism, "Get the Data: Drone Wars," thebureauinvestigates.com (accessed Dec. 18, 2013)

  7. New America Foundation, "The National Security Studies Program," natsec.newamerica.net (accessed Dec. 18, 2013)

  8. Bill Roggio and Alexander Mayer, "Charting the Data for US Airstrikes in Pakistan, 2004-2013," longwarjournal.org, Nov. 29, 2013

  9. Bill Roggio and Bob Barry, "Charting the Data for US Air Strikes in Yemen, 2002-2013," longwarjournal.org, Dec. 12, 2013

  10. New York Times, "Obama's Speech on Drone Policy," nytimes.com, May 23, 2013

  11. Peter Bergen, "Drone Wars: The Constitutional and Counterterrorism Implications of Targeted Killing," Testimony presented before the US Senate Committee on the Judiciary, Subcommittee on the Constitution, Civil Rights, and Human Rights, Apr. 23, 2013

  12. Mehreen Zahra-Malik and Jibran Ahmed, "Pakistani Taliban Chief Killed in Drone Strike," reuters.com, Nov. 1, 2013

  13. William Saletan, "In Defense of Drones," slate.com, Feb. 19, 2013

  14. Paul B. Spiegel and Peter Salama, "War and Mortality in Kosovo, 1998-99: An Epidemiological Testimony," The Lancet, June 24, 2000

  15. Guenter Lewy, America in Vietnam, 1980

  16. William S. Turley, The Second Indochina War: A Concise Political and Military History, 2009

  17. Independent International Commission on Kosovo, "The Kosovo Report," reliefweb.int, Oct. 23, 2000

  18. Eric Ruder, "Remote Control Warfare. Some Sixty US Drone Bases around the World," globalresearch.ca, Apr. 8, 2013

  19. Friends Committee on National Legislation, "Understanding Drones," fcnl.org (accessed Dec. 18, 2013)

  20. Department of Defense, "United States Department of Defense Fiscal Year 2014 Budget Request," comptroller.defense.gov, Apr. 2013

  21. National Priorities Project, "Analysis of the Fiscal Year 2012 Pentagon Spending Request," nationalpriorities.org, May 6, 2013

  22. Mark Thompson, "Costly Flight Hours," nation.time.com, Apr. 2, 2013

  23. Shan Carter and Amanda Cox, "One 9/11 Tally: $3.3 Trillion," nytimes.com, Sep. 8, 2011

  24. Charter of the United Nations, "Chapter VII: Action with Respect to Threats to the Peace, Breaches of the Peace, and Acts of Aggression," un.org (accessed Dec. 18, 2013)

  25. Philip Alston, "Study on Targeted Killings," Report of the Human Rights Council, Fourteenth Session, Agenda Item 3, May 28, 2010

  26. Joshua Foust and Ashley S. Boyle, "The Strategic Context of Lethal Drones: A Framework for Discussion," americansecurityproject.org, Aug. 16, 2012

  27. Harold Koh, "Legal Adviser Koh's Speech on the Obama Administration and International Law, March 2010," cfr.org, Mar. 25, 2010

  28. Leo Van Den Hole, "Anticipatory Self-Defence Under International Law," American University International Law Review, 2003

  29. US Constitution, "Article II," constitution.findlaw.com (accessed Dec. 18, 2013)

  30. Cora Currier, "Drone Strikes Test Legal Grounds for War on Terror," propublica.org, Feb. 6, 2013

  31. US Congress, "Public Law 107-40," gpo.gov, Sep. 18, 2001

  32. Micah Zenko, "How the Obama Administration Justifies Targeted Killings," blogs.cfr.org, July 5, 2012

  33. Barack Obama, "U.S. Policy Standards and Procedures for the Use of Force in Counterterrorism Operations Outside the United States and Areas of Active Hostilities," whitehouse.gov, May 23, 2013

  34. Scott Shane, "Yemen's Leader Praises U.S. Drone Strikes," nytimes.com, Sep. 29, 2012

  35. Fatima Bhutto, "A Flood of Drone Strikes: What the Wikileaks Revelations Tell Us about How Washington Runs Pakistan," huffingtonpost.com, Dec. 9, 2010

  36. Nic Robertson and Greg Botelho, "Ex-Pakistani President Musharraf Admits Secret Deal with U.S. on Drone Strikes," edition.cnn.com, Apr. 12, 2013

  37. Peter Bergen and Jennifer Rowland, "Drones Decimating Taliban in Pakistan," cnn.com, July 3, 2012

  38. Guy Taylor, "U.S. Intelligence Warily Watches for Threats to U.S. Now that 87 Nations Possess Drones," washingtontimes.com, Nov. 10, 2013

  39. Ian Black, "Iran Unveils Bomber Drone that Aims to Deliver Peace and Friendship," theguardian.com, Aug. 22, 2010

  40. Jeremy Page, "China's New Drones Raise Eyebrows," online.wsj.com, Nov. 18, 2010

  41. J.R. Wilson, "2011 Worldwide UAV Roundup," Aerospace America, Mar. 2011

  42. "Unmanned Aerial Vehicles Directory," Flight International, June 21-27, 2005

  43. Teal Group Inc., "Teal Group Predicts Worldwide UAV Market Will Total $89 Billion in Its 2013 UAV Market Profile and Forecast," tealgroup.com, June 17, 2013

  44. Ian Austen, "Libyan Rebels Reportedly Used Tiny Canadian Surveillance Drone," nytimes.com, Aug. 24, 2011

  45. Ashley Fantz, "Hezbollah Claims it Sent Drone Over Israel, but Expert Calls it 'Rinky Dink,'" cnn.com, Oct. 12, 2012

  46. Wayne Chappelle and Kent McDonald, "Occupational Health Stress Screening for Remotely Piloted Aircraft & Intelligence (Distributed Common Ground System) Operators," US Air Force Powerpoint presentation at the Brookings Institution, Nov. 3, 2011

  47. Gallup, Inc., "In U.S., 65% Support Drone Attacks on Terrorists Abroad," gallup.com, Mar. 25, 2013

  48. Howard LaFranchi, "American Public Has Few Qualms with Drone Strikes, Poll Finds," csmonitor.com, June 3, 2013

  49. Jeremy Scahill, "Washington's War in Yemen Backfires," thenation.com, Feb. 14, 2012

  50. Sudarsan Raghavan, "In Yemen, U.S. Airstrikes Breed Anger, and Sympathy for Al-Qaeda," washingtonpost.com, May 29, 2012

  51. Umar Farouk Abdulmutallab, "Transcript: Read Abdulmutallab's Statement on Guilty Plea," freep.com, Oct. 12, 2011

  52. Lorraine Adams and Ayesha Nasir, "Inside the Mind of the Times Square Bomber," theguardian.com, Sep. 18, 2010

  53. Cora Currier and Justin Elliott, "The Drone War Doctrine We Still Know Nothing About," propublica.org, Feb. 26, 2013

  54. Richard Engel and Robert Windrem, "Exclusive: CIA Didn't Always Know Who it Was Killing in Drone Strikes, Classified Documents Show," investigations.nbcnews.com, June 5, 2013

  55. Jonathan S. Landay, "Obama's Drone War Kills 'Others,' Not Just Al Qaida Leaders," mcclatchydc.com, Apr. 9, 2013

  56. Kenneth Anderson and Benjamin Wittes, "Three Deep Flaws in Two New Human-Rights Reports on U.S. Drone Strikes," newrepublic.com, Oct. 24, 2013

  57. Stanford International Human Rights and Conflict Resolution Clinic and Global Justice Clinic at NYU School of Law, "Living Under Drones: Death, Injury and Trauma to Civilians from US Drone Practices in Pakistan," livingunderdrones.org, 2012

  58. CNN Wire Staff, "Drone Strikes Kill, Maim and Traumatize Too Many Civilians, U.S. Study Says," cnn.com, Sep. 25, 2012

  59. Adam Entous, "Special Report: How the White House Learned to Love the Drone," reuters.com, May 18, 2010

  60. Peter Bergen and Megan Braun, "Drone is Obama's Weapon of Choice," cnn.com, Sep. 19, 2012

  61. United Nations, "International Covenant on Civil and Political Rights," un.org, Dec. 19, 1966

  62. Judith Gardam, Necessity, Proportionality and the Use of Force by States, 2011

  63. Christof Heyns, "Extrajudicial Executions and Targeted Killings," International Law Journal symposium on 'State Ethics' at Harvard Law School, Feb. 20, 2012

  64. United Nations, "UN Charter," iilj.org (accessed Dec. 18, 2013)

  65. Eliav Lieblich, "Intervention and Consent: Consensual Forcible Interventions in Internal Armed Conflicts as International Agreements," Boston University International Law Journal, 2011

  66. Amnesty International, "Will I Be Next? US Drone Strikes in Pakistan," amnesty.org, 2013

  67. Micah Zenko, "Transferring CIA Drone Strikes to the Pentagon," cfr.org, Apr. 2013

  68. Russell Brandom, "Why the CIA Isn't Handing Over its Drone Assassins to the Military," theverge.com, Nov. 7, 2013

  69. American Civil Liberties Union, "Al-Aulaqi v. Panetta: Lawsuit Challenging Targeted Killings," aclu.org (accessed Dec. 18, 2013)

  70. Reuters, "Pakistan: Drone Strikes Are Violations of Sovereignty," huffingtonpost.com, June 4, 2012

  71. Jethro Mullen, "Report: Former Drone Operator Shares His Inner Torment," cnn.com, Oct. 25, 2013

  72. BBC News Asia, "US Drone Strikes 'Raise Questions' - UN's Navi Pillay," bbc.co.uk, June 8, 2012

  73. RIA Novosti, "UN Blasts US Drone Strikes in Pakistan," en.ria.ru, Mar. 15, 2013

  74. Andrea Germanos, "UN Expert Challenges Foundations of US Covert Drone War," commondreams.org, Oct. 17, 2013

  75. Chris Cole and Jim Wright, "What Are Drones?," dronewars.net, Jan. 2010

  76. Elisabeth Bumiller, "A Day Job Waiting for a Kill Shot a World Away," nytimes.com, July 29, 2012

  77. Justin Sink, "Dem Lawmaker: Drone Strikes Creating 'Real Enemies' for the US," thehill.com, June 10, 2012

  78. Medea Benjamin, "Medea Benjamin on How Drones May Be Used Against US Citizens Soon," truth-out.org, June 1, 2012

  79. David Alexander, "Retired General Cautions Against Overuse of 'Hated' Drones," reuters.com, Jan. 7, 2013

  80. New America Foundation, "Drone Strikes," pakistansurvey.org (accessed Dec. 18, 2013)

  81. New America Foundation, "Drone Targets," pakistansurvey.org (accessed Dec. 18, 2013)

  82. Pew Research Center, "Pakistani Public Opinion Ever More Critical of U.S.," pewglobal.org, June 27, 2012

  83. Richard Leiby, "Pakistan Calls for End to U.S. Drone Attacks," articles.washingtonpost.com, Apr. 12, 2012

  84. Declan Walsh and Ismail Khan, "Pakistani Party Votes to Block NATO Supply Lines if Drones Persist," nytimes.com, Nov. 4, 2013

  85. Maha El Dahan, "Yemeni Parliament in Non-Binding Vote Against Drone Attacks," reuters.com, Dec. 15, 2013

  86. Jean L. Otto and Bryant J. Webber, "Mental Health Diagnoses and Counseling among Pilots of Remotely Piloted Aircraft in the United States Air Force," Armed Forces Health Surveillance Center Monthly Surveillance Monthly Report, Mar. 2013

  87. James L. Green, "Civil War Ballooning During the Seven Days Campaign," civilwar.org (accessed Dec. 18, 2013)

  88. Finding Dulcinea, "On This Day: Japanese WWII Balloon Bomb Kills 6 in Oregon," findingdulcinea.com, May 5, 2011

  89. Asawin Suebsaeng, "Drones: Everything You Ever Wanted to Know But Were Always Afraid to Ask," motherjones.com, Mar. 5, 2013

  90. Ian G. R. Shaw, "The Rise of the Predator Empire: Tracing the History of U.S. Drones," understandingempire.wordpress.com, 2013

  91. Ian Bott, Cleve Jones, and John Burn-Murdoch, "Great and Small: The Many Types of Drone," ft.com, Oct. 8, 2013

  92. Spencer Ackerman, "Air Force Is Through with Predator Drones," wired.com, Dec. 14, 2010

  93. US Air Force, "'Reaper' Moniker Given to MQ-9 Unmanned Aerial Vehicle," archive.is/FoPi, Sep. 14, 2006

  94. Barack Obama, "Presidential Letter -- 2012 War Powers Resolution 6-Month Report," whitehouse.gov, June 15, 2012

  95. Mark Mazzetti and Scott Shane, "As New Drone Policy Is Weighed, Few Practical Effects Are Seen," nytimes.com, Mar. 21, 2013

  96. Siobhan Gorman and Adam Entous, "CIA Plans Yemen Drone Strikes," online.wsj.com, June 14, 2011

  97. Washington Post, "U.S. Military Drone Network in the Middle East and Africa," apps.washingtonpost.com, July 19, 2013

  98. Jane Mayer, "The Predator War," newyorker.com, Oct. 26, 2009

  99. Phil Stewart, "Pentagon Scraps Medal for Drone Pilots After Uproar," reuters.com, Apr. 15, 2013

  100. Michael Cooney, "Air Force: Unmanned Aircraft Hit 1 Million Combat Hours," networkworld.com, June 22, 2011

  101. US Air Force News Service, "RPAs Reach 2 Million Hours," suasnews.com, Oct. 25, 2013

  102. Jill Replogle, "The Drone Makers and Their Friends in Washington," kpbs.org, July 5, 2012

  103. CBC News, "Evolution of the Drone Strike," cbc.ca, Feb. 6, 2013

  104. Micah Zenko, "Reforming U.S. Drone Strike Policies," cfr.org, Jan. 2013

  105. Cora Currier, "6 Months After Obama promised to Divulge More on Drones, Here's What We Still Don't Know," propublica.org, Nov. 6, 2013

  106. Mark Mazzetti, "A Secret Deal on Drones, Sealed in Blood," nytimes.com, Apr. 6, 2013

  107. Greg Miller and Bob Woodward, "Secret Memos Reveal Explicit Nature of U.S., Pakistan Agreement on Drones," washingtonpost.com, Oct. 24, 2013

  108. Declan Walsh, "In Pakistan, Drone Strike Turns a Villain Into a Victim," nytimes.com, Nov. 3, 2013

  109. Adam Baron, "With AQAP's Strategy Unclear, Yemen Struggles to Respond," csmonitor.com, Aug. 7, 2013

  110. American Civil Liberties Union, "Predator Drone FOIA," aclu.org (accessed Aug. 14, 2013)

  111. American Civil Liberties Union, "Appeals Court to Hear Oral Argument Tuesday in ACLU FOIA Lawsuit Seeking Targeted Killing Memos," aclu.org, Sep. 30, 2013

  112. David G. Savage, "Federal Court Rejects CIA's Denial of Drone Strikes as 'Fiction,'" articles.latimes.com, Mar. 15, 2013

  113. PolicyMic, "Obama Has No Interest in Changing His Drone Strike Policy," policymic.com, Aug. 14, 2013

  114. Mark Mazzetti, Charlie Savage, and Scott Shane, "How a U.S. Citizen Came to Be in America's Cross Hairs," nytimes.com, Mar. 9, 2013

  115. US Department of Justice, "Lawfulness of a Lethal Operation Directed Against a U.S. Citizen Who Is a Senior Operational Leader of Al-Qa'ida or an Associated Force," msnbcmedia.msn.com, Feb. 4, 2013

  116. Erica Werner, "Obama Google Plus Hangout: During Q&A, President Offers to Look at Resume of Man Looking for Work (VIDEO)," huffingtonpost.com, Jan. 30, 2012

  117. Karen DeYoung, "A CIA Veteran Transforms U.S. Counterterrorism Policy," articles.washingtonpost.com, Oct. 24, 2012

  118. United States Senate Select Committee on Intelligence, "Open Hearing on the Nomination of John O. Brennan to Be Director of the Central Intelligence Agency," intelligence.senate.gov, Feb. 7, 2013

  119. Senate Judiciary Committee, Subcommittee on the Constitution, Civil Rights and Human Rights, "Drone Wars: The Constitutional and Counterterrorism Implications of Targeted Killing," judiciary.senate.gov, Apr. 22, 2013

  120. Micah Zenko, "The Intercept’s ‘Drone Papers’ Revelations Mandate a Congressional Investigation," foreignpolicy.com, Oct. 15, 2015

  121. Andy Greenberg, "A Second Snowden Has Leaked a Mother Lode of Drone Docs," wired.com, Oct. 15, 2015

  122. Scott Shackford, "A New Whistleblower Exposes America’s Drone Assassinations," reason.com, Oct. 15, 2015

Sources:

CBC News, "Evolution of the Drone Strike," cbc.ca, Feb. 6, 2013

The Economist, "Drop the Pilot," economist.com, Oct. 19, 2013

Peter L. Bergen, "Warrior in Chief," nytimes.com, Apr. 28, 2012

James Chastain, "Venice and the Revolution of 1848-49," ohio.edu, Oct. 27, 2004

Mark Hosenball, "House Committee Rejects Provision Requiring Account of Drone Casualties," reuters.com, Nov. 21, 2013

Mark Hosenball, "Senate Panel Approves Beefed-Up Oversight of Drone Attacks," usnews.nbcnews.com, Nov. 8, 2013

Chris Kirk, "Obama's 262 Drone Strikes in Pakistan," slate.com, June 8, 2012

Mark Mazzetti and Scott Shane, "Drones Are Focus as CIA Nominee Goes Before Senators," nytimes.com, Feb. 7, 2013

Russell Naughton, "Remote Piloted Aerial Vehicles: An Anthology," ctie.monash.edu, Feb. 2, 2003