¹ See, e.g., Mission Creep: The Militarization of US Foreign Policy? (Gordon Adams & Shoon Murray eds., 2014); David H. Ucko, The New Counterinsurgency Era: Transforming the U.S. Military for Modern Wars (2009); Stewart Patrick & Kaysie Brown, The Pentagon and Global Development: Making Sense of the DoD's Expanding Role (Center for Global Development, Working Paper No. 131, Nov. 2007), available at https:// www.cgdev.org/files/14815_file_PentagonandDevelopment.pdf (addressing the Department of Defense's growing aid role, including foreign aid policy, training, and equipping foreign military beyond theaters of war).

² Office of the Director of National Intelligence, Summary of Information Regarding U.S. Counterterrorism Strikes Outside Areas of Active Hostilities (2016), available at https://www.dni.gov/files/documents/Newsroom/Press%20Releases/DNI+Release+on+CT+Strikes+Outside+Areas+of+Active+Hostilities.PDF.

³ One of many useful summaries of this body of law is: Doswald-Beck, Louise, The Right to Life in Armed Conflict: Does International Humanitarian Law Provide All the Answers? , 88 Int'l Rev. Red Cross 881 (2006)CrossRefGoogle Scholar, available at https://www.icrc.org/eng/assets/files/other/irrc_864_doswald-beck.pdf; see also Laurie R. Blank & Gregory P. Noone, International Law and Armed Conflict: Fundamental Principles and Contemporary Challenges in the Law of War (2013).

⁴ Remarks of U.S. President Barack Obama at National Defense University (May 23, 2013), at https://obamawhitehouse.archives.gov/the-press-office/2013/05/23/remarks-president-national-defense-university (“[O]ur commitment to Constitutional principles has weathered every war, and every war has come to an end.”); see also Remarks of Jeh Charles Johnson, General Counsel of the U.S. Department of Defense at the Oxford Union, Oxford University (Nov. 30, 2012), available at https://www.state.gov/documents/organization/211954.pdf (“[O]n the present course, there will come … a tipping point at which so many of the leaders and operatives of al Qaeda and its affiliates have been killed or captured, and the group is no longer able to attempt or launch a strategic attack against the United States, such that al Qaeda as we know it, the organization that our Congress authorized the military to pursue in 2001, has been effectively destroyed.”).

⁵ Concerns about weapons technologies and the (resulting) rising power of small groups of nonstate actors have been detailed in the security literature for years. See, e.g., Greninger, Christopher F. Chyba & Alexander L., Biotechnology and Bioterrorism: An Unprecedented World , 46 Survival 143 (2004)Google Scholar.

⁶ The book quotes: David Barno & Nora Bensahel, Fighting and Winning in the ‘Gray Zone’, War on the Rocks (May 19, 2015), at https://warontherocks.com/2015/05/fighting-and-winning-in-the-gray-zone.

⁷ See Pearlstein, Deborah N., The Soldier, the State, and the Separation of Powers , 90 Tex. L. Rev. 797 (2012)Google Scholar (discussing constitutional history).

⁸ On the history of the legal status of federal Indian tribes, see, for example, Norgren, Jill, Protection of What Rights They Have: Original Principles of Federal Indian Law , 64 N.D. L. Rev. 73 (1988)Google Scholar. On the history of U.S. military operations against the Indian tribes, see, for example, Pritzker, Barry M., First Seminole War , in The Encyclopedia of North American Indian Wars, 1607–1890: A Political, Social, and Military History 715, 716 (2010)Google Scholar.

⁹ Youngstown Sheet & Tube Co. v. Sawyer, 343 U.S. 579, 587 (1952) (acknowledging the government's argument that “‘theater of war’ be an expanding concept”).

¹⁰ See, e.g., Monica Hakimi, Taking Stock of the Law on Targeting, EJIL: Talk! (Dec. 12, 2016), at https://www.ejiltalk.org/taking-stock-of-the-law-on-targeting-part-i; Michael J. Adams & Ryan Goodman, De Facto and De Jure Non-international Armed Conflicts: Is It Time to Topple Tadić?, Just Security (Oct. 13, 2016), at https:// www.justsecurity.org/33533/de-facto-de-jure-non-international-armed-conflicts-time-topple-tadic; Deborah Pearlstein, The NIAC Threshold, Opinio Juris (Oct. 4, 2016), at http://opiniojuris.org/2016/10/04/the-niac-threshold; Adil Ahmad Haque, Triggers and Thresholds of Non-international Armed Conflict, Just Security (Sept. 29, 2016), at https://www.justsecurity.org/33222/triggers-thresholds-non-international-armed-conflict.

¹¹ Prosecutor v. Tadić, Case No. IT-94-1-T, Opinion and Judgment, paras. 688–93 (Int'l Crim. Trib. for the Former Yugoslavia May 7, 1997).

¹² See, e.g., Prosecutor v. Haradinaj, Case No. IT-04-84-A, Judgment (Int'l Crim. Trib. for the Former Yugoslavia July 19, 2010).

¹³ See, e.g., id.; C-285/12, Aboubacar Diakité v. Commissaire Général aux Réfugiés et aux Apatrides, ECLI: EU:C:2014:39 (Ct. Just. E.U. Jan. 30, 2014); United States v. Hamdan, 801 F. Supp. 2d 1247, 1278 & n. 54 (U.S. Ct. Mil. Comm'n Rev. 2011) (en banc), rev'd Hamdan II, 696 F.3d 1238 (D.C. Cir. 2012), overruled on other grounds by Al Bahlul v. United States, 2014 WL 3437485 (D.C. Cir. July 14, 2014).

¹⁴ Prosecutor v. Tadić, supra note 11, at 562 (describing the need for factors to distinguish a non-international armed conflict (NIAC) from “banditry, unorganized and short-lived insurrections, or terrorist activities, which are not subject to international humanitarian law”).

¹⁵ See, e.g., Vite, Sylvain, Typology of Armed Conflicts in International Humanitarian Law: Legal Concepts and Actual Situations , 91 Int'l Rev. Red Cross 69 (2009)CrossRefGoogle Scholar; Gasser, Hans-Peter, Internationalized Non-international Armed Conflicts: Case Studies of Afghanistan, Kampuchea, and Lebanon , 33 Am. U. L. Rev 145 (1983)Google Scholar.

¹⁶ See Protocol Additional to the Geneva Conventions of 12 August 1949, and Relating to the Protection of Victims of International Armed Conflicts [Protocol I], Art. 46, June 8, 1977, 1125 UNTS 3.

¹⁷ See, e.g., FISA Amendments Act of 1978, 50 U.S.C. § 1801 et seq. (regulating domestic intelligence surveillance); Exec. Order No. 12333, 46 Fed. Reg. 59941 (1981) (regulating bulk communications collection under Article II of the U.S. Constitution in any “lawful foreign intelligence, counterintelligence, international narcotics or international terrorism investigation”).

¹⁸ See, e.g., Geneva Convention [III] Relative to the Treatment of Prisoners of War, Arts. 12, 33, Aug. 12, 1949, 6 UST 3316, 75 UNTS 135 [hereinafter GC III].

¹⁹ Id. Art. 3 (requiring only that “[p]ersons taking no active part in the hostilities, including … those placed hors de combat by … detention … shall in all circumstances be treated humanely …”).

²⁰ For discussions of various U.S. and foreign security detention regimes and their legality, see, for example, articles included in the 2009 symposium issue of the Case Western International Law Journal on this topic, beginning with Scharf, Michael S. and Gillespie, Gwen, Foreword: Security Detention , 40 Case W. Res. J. Int'l L. 315 (2009)Google Scholar.

²¹ U.S. Const. amend. V.

²² GC III, supra note 18, Art. 3(I)(c).

²³ Hart, H.L.A., Positivism and the Separation of Law and Morals , 71 Harv. L. Rev. 593, 607–08 (1958)CrossRefGoogle Scholar (“A legal rule forbids you to take a vehicle into the public park. Plainly this forbids an automobile, but what about bicycles, roller skates, toy automobiles? What about airplanes? … There must be a core of settled meaning, but there will be, as well, a penumbra of debatable cases in which words are neither obviously applicable nor obviously ruled out… . Human invention and natural processes continually throw up such variants on the familiar, and if we are to say that these ranges of facts do or do not fall under existing rules, then the classifier must make a decision which is not dictated to him … . [I]n applying legal rules, someone must take the responsibility of deciding that words do or do not cover some case in hand… .”).

²⁴ See, e.g., supra, notes 11–15. While Hamdan v. Rumsfeld is often cited for the proposition that there exists between the United States and Al Qaeda a transnational NIAC, the Hamdan Court was in fact careful to limit its holding to the conflict between those parties then occurring “in the territory” of Afghanistan. Hamdan v. Rumsfeld, 548 U.S. 557, 630 (2006).

²⁵ See, e.g., Hakimi, Monica, A Functional Approach to Targeting and Detention , 110 Mich. L. Rev. 1365 (2012)Google Scholar; Goodman, Ryan, The Power to Kill or Capture Enemy Combatants 24 Eur. J. Int'l L. 819–20 (2013)CrossRefGoogle Scholar (arguing that the modern law of armed conflict should be understood to require, in certain circumstances, that “if enemy combatants can be put out of action by capturing them, they should not be injured; if they can be put out of action by injury, they should not be killed …”). But see Geoffrey Corn, Laurie Blank, Christopher Jenks & Eric Talbot Jensen, Capture Instead of Kill: A Dangerous Conflation of Law and Policy, Lawfare (Feb. 25, 2013).

²⁶ Report on the Legal and Policy Frameworks Guiding the United States Use of Military Force and Related National Security Operations (Dec. 2016), available at https://fas.org/man/eprint/frameworks.pdf.

²⁷ Id.

²⁸ See, e.g., Christopher M. Blanchard & Carla E. Humud, The Islamic State and U.S. Policy (Congressional Research Service, Feb. 2, 2017), available at https://fas.org/sgp/crs/mideast/R43612.pdf (summarizing background on the Islamic State organization, including “goals, operations, and affiliates…”) [hereinafter CRS Islamic State Report]; Carla E. Humud, Al Qaeda and U.S. Policy: Middle East and Africa (Congressional Research Service, Aug. 11, 2016), available at https://fas.org/sgp/crs/mideast/R43756.pdf (discussing Al Qaeda leadership and affiliates) [hereinafter CRS Al Qaeda Report].

²⁹ See, e.g., CRS Islamic State Report, supra note 28, at 18, 26 (discussing goals of “reestablishment of the caliphate” and protecting “true Muslim believers from threats posed by idolaters, apostates, and other non-believers”); CRS Al Qaeda Report, supra note 28, at 10–11 (describing the group's focus on targeting America and on avoiding conflict with local governments).

³⁰ The U.S. Department of Defense reported twenty-nine U.S. military deaths in action in operations in Afghanistan from January 1, 2015 through September 11, 2017; and twelve U.S. military deaths in action in operations in Iraq and Syria from Oct. 15, 2014 through September 11, 2017. U.S. Defense Department Casualty Status Statistics, available at https://www.defense.gov/casualty.pdf. For some perspective, the U.S. Army reports that sixty-four soldiers died in on-duty accidents in fiscal years 2014–2016. U.S. Army Accident Statistics, available at https://safety.army.mil/Portals/0/Documents/STATISTICS/Standard/PublicReports/ArmyAccidentStatisticsYearEndData.pdf. Solely considering U.S. military deaths in operations against Al Qaeda and the Taliban in Afghanistan, and against ISIS in Syria and Iraq, is a terribly incomplete measurement of the intensity of the conflicts between the United States and these groups. But given the absence of reliable, unclassified statistics about enemy deaths at U.S. hands in these conflicts, it is one of few concrete indicia available to the public.

³¹ See supra text accompanying notes 11–15.

³² David E. Sanger & Steven Erlangermarch, Suspicion Falls on Russia as ‘Snake’ Cyberattacks Target Ukraine's Government, N.Y. Times (Mar. 8, 2014).

³³ See U.N. Charter Art. 51 (“Nothing in the present Charter shall impair the inherent right of individual or collective self-defence if an armed attack occurs against a Member of the United Nations …”); see also Yoram Dinstein, War, Aggression and Self-Defense (5th ed. 2011).

³⁴ U.S. and allied estimates of the number of ISIS fighters killed since coalition strikes began in 2014 vary radically. See, e.g., Ryan Browne, UK Puts Number of ISIS Fighters Killed at Half US Figure, CNN (Dec. 16, 2016), at http://www.cnn.com/2016/12/16/politics/uk-us-number-isis-fighters-killed (citing figures from 50,000 to 25,000 to 2,500 ISIS fighters killed by coalition forces).

³⁵ See supra note 30 (U.S. military deaths in operations against Al Qaeda, the Taliban, and ISIS).

³⁶ Prosecutor v. Haradinaj, supra note 12, at 49