text: Chapter 8
  8-63. An accused who is not a U.S. citizen and who meets the definition of an unprivileged enemy belligerent
  under the terms of the MCA is subject to trial before a military commission or in Federal court pursuant to
  U.S. law (see paragraph 8-55).
  Sanctions Against Misconduct in Other Military Operations
  8-64. When war crimes are charged as “war crimes,” the applicable criminal statutes generally also provide
  a requirement that the conduct occur in the context of and in association with an “armed conflict” (see, 18
  U.S.C. § 2441). While U.S. military personnel may engage in operations that do not involve armed conflict,
  it is DOD policy to comply with LOAC in all military operations regardless of how they are characterized
  (DODD 2311.01E para. 4.1). The specific criminal sanctions available to enforce compliance with these
  standards may vary, however, depending on the relationship with other sovereign States in any given
  operation, especially the host nation. The United States always abides by the “law of the flag”—the legal
  standards and enforcement mechanisms it brings with the force. Sometimes U.S. service members engaged
  in peace operations or other military operations short of armed conflict are subject to the laws of the nation
  in which the activity is conducted, which laws may be more restrictive concerning the use of force than may
  be permitted under multinational force rules of engagement (JP 3-07.3 para. 3(h)). In general, the application
  of host-nation law to these other operations is governed by an international agreement, such as a status-of-
  forces agreement or, for United Nations operations, a status of mission agreement (JP 3-07.3 para. 7(b)).
  These agreements define the circumstances under which the host nation may exercise jurisdiction over peace
  operations personnel (both military and civilian) who commit crimes in the host nation. In all cases, however,
  the UCMJ will apply to the activities of U.S. service members, regardless of the nature of the operation or
  where the potential crime occurs (RCM 203).
  PENALTIES
  8-65. Penalties vary depending on the war crime committed and the law pursuant to which the crime is being
  prosecuted. Authorized punishments can range from fines or letters of reprimand to death. For instance, for
  the offense of murder under the UCMJ, the accused may be subject to death or life imprisonment (UCMJ,
  art. 118). Crimes under the War Crimes Act, the MCA, or other U.S. law also carry significant penalties.
  Generally, violations of the War Crimes Act that result in the death of a victim may be punishable by death
  (18 U.S.C. § 2441(a)). Grave breaches that authorize the death penalty include willful killing, torture,
  inhumane treatment, or willfully causing great suffering or injury (GWS art. 50; GWS Sea art. 51; GPW art.
  130; GC art. 147).
  DEFENSES
  8-66. The availability of legal defenses to charges of war crimes may depend on the specific jurisdiction and
  forum in which charges are brought. The following general information regarding affirmative defenses that
  negate criminal responsibility under general principles of criminal law and war crimes may be helpful, but
  commanders should request legal advice if they have specific questions.
  General Legal Defenses
  8-67. Individuals being tried by a U.S. court-martial for war crimes (either as violations of the UCMJ, as
  violations of other Federal law, or as LOAC violations) may assert legal defenses available under the UCMJ
  (RCM 916; MMC pt. II, Rule 916).
  Justification
  8-68. A death, injury, or other act caused or done in the proper performance of a legal duty is justified and
  not unlawful. This includes a privileged belligerent’s killing of an enemy combatant in combat and other acts
  that would otherwise be offenses under local criminal law (RCM 916(c) Discussion; MMC, pt. II, Rule
  916(c)).