The Hague Conventions were international treaties negotiated at the First and Second Peace Conferences at The Hague, Netherlands, in 1899 and 1907, respectively, and were, along with the Geneva Conventions, among the first formal statements of the laws of war and war crimes in the nascent body of secular international law.
The Geneva Conventions are four related treaties adopted and continuously expanded from 1864 to 1949 that represent a legal basis and framework for the conduct of war under international law. Every single member state of the United Nations has currently ratified the conventions, which are universally accepted as customary international law, applicable to every situation of armed conflict in the world. However, the Additional Protocols to the Geneva Conventions adopted in 1977 containing the most pertinent, detailed and comprehensive protections of international humanitarian law for persons and objects in modern warfare are still not ratified by several states continuously engaged in armed conflicts, namely the United States, Israel, India, Pakistan, Iraq, Iran, and others. Accordingly, states retain different codes and values about wartime conduct. Some signatories have routinely violated the Geneva Conventions in a way that either uses the ambiguities of law or political maneuvering to sidestep the laws' formalities and principles.
The first three conventions have been revised and expanded, with the fourth one added in 1949:
The First Geneva Conventionfor the Amelioration of the Condition of the Wounded and Sick in Armed Forces in the Field was adopted in 1864 and then significantly revised and replaced by the 1906 version, the 1929 version, and later the First Geneva Convention of 1949.
The Second Geneva Conventionfor the Amelioration of the Condition of Wounded, Sick and Shipwrecked Members of Armed Forces at Sea was adopted in 1906 and then significantly revised and replaced by the Second Geneva Convention of 1949.
Just after WWI the world governments started to try and systematically create a code for how War Crimes would be defined. Their first outline of a law was "Instructions for the Government of Armies of the United States in the Field"—also known as the “Lieber Code.”  A small number of German military personnel of the First World War were tried in 1921 by the German Supreme Court for alleged war crimes.
Also known as the Tokyo Trial, the Tokyo War Crimes Tribunal or simply as the Tribunal, it was convened on May 3, 1946, to try the leaders of the Empire of Japan for three types of crimes: "Class A" (crimes against peace), "Class B" (war crimes), and "Class C" (crimes against humanity), committed during World War II.
Bodies of some of the hundreds of Vietnamese villagers who were killed by U.S. soldiers during the My Lai Massacre
On July 1, 2002, the International Criminal Court, a treaty-based court located in The Hague, came into being for the prosecution of war crimes committed on or after that date. Several nations, most notably the United States, China, Russia, and Israel, have criticized the court. The United States still participates as an observer. Article 12 of the Rome Statute provides jurisdiction over the citizens of non-contracting states if they are accused of committing crimes in the territory of one of the state parties.
War crimes are defined in the statute that established the International Criminal Court, which includes:
Grave breaches of the Geneva Conventions, such as:
Willful killing, or causing great suffering or serious injury to body or health
Former SerbianPresidentSlobodan Milošević was brought to trial charges with, genocide, crimes against humanity, and war crimes in three republics. This pertained to superior responsibility for the Bosnia and Croatia indictments, and individual responsibility for the Kosovo indictment. He was acquitted, however, as he died in custody in 2006, before the trial could be concluded.
Former Liberian PresidentCharles G. Taylor was also brought to The Hague charged with war crimes; his trial stretched from 2007 to March 2011. He was convicted in April 2012 of aiding and abetting crimes against humanity.
Ratko Mladić, indicted for genocide amongst other violations of humanitarian law during the Bosnian War; he was captured in Serbia in May 2011 and was extradited to face trial in The Hague, wherein he was found guilty and sentenced to life in prison.
Under the Nuremberg Principles, war crimes are different from crimes against peace. Crimes against peace include planning, preparing, initiating, or waging a war of aggression, or a war in violation of international treaties, agreements, or assurances. Because the definition of a state of "war" may be debated, the term "war crime" itself has seen different usage under different systems of international and military law. It has some degree of application outside of what some may consider being a state of "war", but in areas where conflicts persist enough to constitute social instability.
Controversy arose when the Allies re-designated German POWs (under the protection of the 1929 Geneva Convention on Prisoners of War) as Disarmed Enemy Forces (allegedly unprotected by the 1929 Geneva Convention on Prisoners of War), many of which were then used for forced labor such as clearing minefields. By December 1945, six months after the war had ended, it was estimated by French authorities that 2,000 German prisoners were still being killed or maimed each month in mine-clearing accidents. The wording of the 1949 Third Geneva Convention was intentionally altered from that of the 1929 convention so that soldiers who "fall into the power" following surrender or mass capitulation of an enemy are now protected as well as those taken prisoner in the course of fighting.
Torture or inhuman treatment, including biological experiments;
Willfully causing great suffering, or serious injury to body or health;
Compelling a prisoner of war or other protected person to serve in the forces of hostile power;
Use by children under the age of sixteen years into armed forces or groups or using them to participate actively in hostilities;
Intentionally directing attack against the civilian population as not taking direct part in hostilities;
Extensive destruction and appropriation of property, not justified by military necessity and carried out unlawfully and wantonly;
Destroying or seizing the property of an adversary unless demanded by necessities of the conflict;
Using poison or poisoned weapons;
Intentionally directing attack against building dedicated to religion, education, art, science or charitable purposes, historic monuments, hospitals as long as it's not used as military infrastructure;
Wilfully depriving a prisoner of war or other protected person of the rights of fair and regular trial;
Attacking or bombarding towns, villages, dwellings or buildings which are undefended and which are not military infrastructure;
Unlawful deportation, transfer, or unlawful confinement;
Taking of hostages.
Intentional assault with the knowledge that such an assault would result in loss of life or casualty to civilians or damage to civilian objects or extensive, long-term and severe damage to the natural environment that would be clearly excessive in relation to the concrete and direct.
Under the law of armed conflict (LOAC), the death of non-combatants is not necessarily a violation; there are many things to take into account. Civilians cannot be made the object of an attack, but the death/injury of civilians while conducting an attack on a military objective are governed under principles such as of proportionality and military necessity and can be permissible. Military necessity "permits the destruction of life of ... persons whose destruction is incidentally unavoidable by the armed conflicts of the war; ... it does not permit the killing of innocent inhabitants for purposes of revenge or the satisfaction of a lust to kill. The destruction of property to be lawful must be imperatively demanded by the necessities of war."
For example, conducting an operation on an ammunition depot or a terrorist training camp would not be prohibited because a farmer is plowing a field in the area; the farmer is not the object of attack and the operations would adhere to proportionality and military necessity. On the other hand, an extraordinary military advantage would be necessary to justify an operation posing risks of collateral death or injury to thousands of civilians. In "grayer" cases the legal question of whether the expected incidental harm is excessive may be very subjective. For this reason, States have chosen to apply a "clearly excessive" standard for determining whether a criminal violation has occurred.
When there is no justification for military action, such as civilians being made the object of attack, a proportionality analysis is unnecessary to conclude that the attack is unlawful.
International Criminal Tribunal for the former Yugoslavia
For aerial strikes, pilots generally have to rely on information supplied by external sources (headquarters, ground troops) that a specific position is in fact a military target. In the case of former Yugoslavia, NATO pilots hit a civilian object (the Chinese embassy in Belgrade) that was of no military significance, but the pilots had no idea of determining it aside from their orders. The committee ruled that "the aircrew involved in the attack should not be assigned any responsibility for the fact they were given the wrong target and that it is inappropriate to attempt to assign criminal responsibility for the incident to senior leaders because they were provided with wrong information by officials of another agency". The report also notes that "Much of the material submitted to the OTP consisted of reports that civilians had been killed, often inviting the conclusion to be drawn that crimes had therefore been committed. Collateral casualties to civilians and collateral damage to civilian objects can occur for a variety of reasons."
The Rendulic Rule is a standard by which commanders are judged.
German General Lothar Rendulic was charged for ordering extensive destruction of civilian buildings and lands while retreating from a suspected enemy attack in what is called scorched earth policy for the military purpose of denying the use of ground for the enemy. The German troops retreating from Finnish Lapland believed Finland would be occupied by Soviet troops and destroyed many settlements while retreating to Norway under the command of Rendulic. He overestimated the perceived risk but argued that Hague IV authorized the destruction because it was necessary to war. He was acquitted of that charge.
Under the "Rendulic Rule" persons must assess the military necessity of an action based on the information available to them at that time; they cannot be judged based on information that subsequently comes to light.
^Protocol Additional to the Geneva Conventions of August 12, 1949, and relating to the Protection of Victims of International Armed Conflict, International Committee of the Red Cross, Geneva, Switzerland.(Protocol I)Archived December 10, 2008, at the Wayback Machine
^ abS. P. MacKenzie "The Treatment of Prisoners of War in World War II" The Journal of Modern History, Vol. 66, No. 3. (Sep. 1994), pp. 487–520.
^ICRCCommentaries on the Convention (III) relative to the Treatment of Prisoners of WarArchived April 4, 2013, at the Wayback MachineArticle 5Archived October 23, 2013, at the Wayback Machine "One category of military personnel which was refused the advantages of the Convention in the course of the Second World War comprised German and Japanese troops who fell into enemy hands on the capitulation of their countries in 1945 (6). The German capitulation was both political, involving the dissolution of the Government, and military, whereas the Japanese capitulation was the only military. Moreover, the situation was different since Germany was a party to the 1929 Convention and Japan was not. Nevertheless, the German and Japanese troops were considered as surrendered enemy personnel and were deprived of the protection provided by the 1929 Convention relative to the Treatment of Prisoners of War."
^Germany (Territory under Allied occupation, 1945–1955: U.S. Zone) (1997). Trials of war criminals before the Nuernberg Military Tribunals under Control Council law no. 10, Nuremberg, October 1946-April, 1949. William S. Hein. ISBN1575882159. OCLC37718851.
^ abDepartment of Defense law of war manual. United States Department of Defense Office of General Counsel. OCLC953877027.