During World War II, the German Wehrmacht (combined armed forcesHeer, Kriegsmarine, and Luftwaffe) committed systematic war crimes, including massacres, mass rape, looting, the exploitation of forced labour, the murder of three million Soviet prisoners of war, and participated in the extermination of Jews. While the Nazi Party's own SS forces (in particular the SS-Totenkopfverbände, Einsatzgruppen and Waffen-SS) was the organization most responsible for the Holocaust, the regular armed forces of the Wehrmacht committed many war crimes of their own (as well as assisting the SS in theirs), particularly on the Eastern Front.

Estimates of the percentage of Wehrmacht soldiers who committed war crimes vary greatly, from the single digits to the vast majority. Historians Alex J. Kay and David Stahel argue that, including crimes such as rape, forced labour, wanton destruction, and looting in addition to murder, "it would be reasonable to conclude that a substantial majority of the ten million Wehrmacht soldiers deployed at one time or another in the German-Soviet War were involved or complicit in criminal conduct". The German Wehrmacht is regarded as being a "crucial factor in the most horrendous crime perpetrated by any nation in modern history" in regard to genocides committed by the regime.

Creation of the Wehrmacht When the Nazi Party came to power, this was welcomed by almost the entire officer corps of the Reichswehr because of the Nazis' support for Wiederwehrhaftmachung (remilitarization) of Germany, the German rearmament and the total militarization of German society in order to ensure that Germany did not lose the next war. As such, what both the Nazi Regime and the German Army wanted to see was a totally militarized Volksgemeinschaft (people's community) that would be purged of perceived internal enemies like the Jews, who many believed had "stabbed Germany in the back" in 1918. The Wehrmacht was created by Adolf Hitler in 1935 with the passing of a law introducing conscription. It was composed of both volunteers and conscripts.

Many officers therefore willingly embraced Nazi ideology in the 1930s. Acting on his own initiative, the Defence Minister Werner von Blomberg had purged the Army of all its Jewish personnel in February 1934. On December 8, 1938, the Army leadership instructed all officers to be thoroughly versed in National Socialism and to apply its values in all situations. Starting in February 1939, pamphlets were issued that were made required reading in the Army. The content can be gauged by the titles: "The Officer and Politics", "Hitler's World Historical Mission", "The Army in the Third Reich", "The Battle for German Living Space", "Hands off Danzig!", and "The Final Solution of the Jewish Question in the Third Reich". The latter essay proclaimed: Attitudes like these colored all of the instructions that came to Wehrmacht troops in the summer of 1939 as a way of preparing for the attack on Poland.

Criminal orders During the planning for the invasion of the Soviet Union, a number of orders were devised by the Wehrmacht leadership. The orders contravened international law and established codes of conduct and became known collectively as "Criminal Orders". The orders were essentially a declaration of war against the civilian population.

In November 1935, the psychological war laboratory of the Reich Ministry of War submitted a study about how best to undermine Red Army morale should a German-Soviet war break out. Working closely with the émigré Russian Fascist Party based in Harbin, the German psychological warfare unit created a series of pamphlets written in Russian for distribution in the Soviet Union. Much of it was designed to play on Russian antisemitism, with one pamphlet calling the "Gentlemen commissars and party functionaries" a group of "mostly filthy Jews". The pamphlet ended with the call for "brother soldiers" of the Red Army to rise up and kill all of the "Jewish commissars".

Although this material was not used at the time, later in 1941 the material the psychological war laboratory had developed in 1935 was dusted off, and served as the basis not only for propaganda in the Soviet Union but also for propaganda within the Wehrmacht. Before Operation Barbarossa, German troops were exposed to violent antisemitic and anti-Slavic indoctrination via movies, radio, lectures, books and leaflets. The lectures were delivered by "National Socialist Leadership Officers", who were appointed for that purpose, and by their junior officers. German Army propaganda portrayed the Soviet enemy in the most dehumanized terms, depicting the Red Army as a force of Slavic Untermenschen (sub-humans) and "Asiatic" savages engaging in "barbaric Asiatic fighting methods" commanded by evil Jewish commissars to whom German troops were to grant no mercy.

British historian Richard J. Evans wrote that junior officers tended to be especially zealous National Socialists, with a third of them being Nazi Party members in 1941. The Wehrmacht did not just obey Hitler's criminal orders for Barbarossa because of obedience, but rather because they shared Hitler's belief that the Soviet Union was run by Jews, and that it was necessary for Germany to completely destroy "Judeo-Bolshevism".

Commissar Order

The Guidelines for the Treatment of Political Commissars cast the war against the Soviet Union as one of ideological and racial differences, and it provided for the immediate liquidation of political commissars in the Red Army. The order was formulated in 1941 with the participation of the Army High Command (the OKH) and issued by the Wehrmacht High Command (the OKW). General Franz Halder welcomed it, writing that "Troops must participate in the ideological battle in the Eastern campaign to the end".

On 17 July 1941, the OKW declared that the Wehrmacht was to:[F]ree itself from all elements among the prisoners of war considered Bolshevik driving forces. The special situation of the Eastern Campaign therefore demands special measures [a euphemism for killing] which are to be carried out free from bureaucratic and administrative influence and with a willingness to accept responsibility. While so far the regulations and orders concerning prisoners of war were based solely on military considerations, now the political objective must be attained, which is to protect the German nation from Bolshevik inciters and forthwith take the occupied territory strictly in hand. As such, all Soviet POWs considered to be commissars together with all Jewish POWs were to be handed over to the Einsatzgruppen to be shot. The OKW attached great importance to the killings of POWs believed to be commissars as it was believed that if the captured commissars reached POW camps in Germany that they would stage another German Stab-in-the-back like that believed to have caused Germany's defeat in World War I. Between July–October 1941, between 580,000 and 600,000 POWs in Wehrmacht custody were turned over to the SS to be killed. In September 1941, both Helmuth James von Moltke and Admiral Wilhelm Canaris wrote memos pointing out to the OKW that the order of July 17, 1941 was illegal under international law.

In particular, both Moltke and Admiral Canaris noted that the German claim that Soviet POWs had no rights because the Soviet Union had not ratified the Geneva Convention was invalid, as Germany had ratified the Geneva Convention and thus under international law was obliged to provide humane treatment for the POWs in its care. In response, Field-Marshal Wilhelm Keitel wrote: "These scruples accord with the soldierly concepts of a chivalrous war! Here we are concerned with the extermination of an ideology. That is why I approve and defend this measure".

In the summer of 1942, there was an illusory liberalization of the treatment of captured political officers. On 10 June, the Gestapo chief Heinrich Müller issued an order on the segregation of prisoners and ordered that commissars be isolated from the rest of the prisoners and sent to Mauthausen-Gusen concentration camp. However, this did not change the plight of commissars much, as Mauthausen was one of the worst Nazi concentration camps where they usually waited for a slow death. On 20 October 1942, Müller again ordered commissars captured in battle to be shot on the spot. Only those commissars who were identified as deserters were sent to Mauthausen. In the following months, reports continued to be filed regarding the executions of Soviet commissars. The last known account of the liquidation of a political officer came from units of Army Group South in July 1943.

The historian Jürgen Förster wrote that the majority of Wehrmacht officers sincerely believed that most Red Army commissars were Jews and that the best way to defeat the Soviet Union was to kill all of the commissars so as to deprive the Soviet soldiers of their Jewish leaders.

Barbarossa Decree

The background behind the Barbarossa Decree was laid out by Hitler during a high-level meeting with military officials on 30 March 1941, where he declared that war against Soviet Russia would be a war of extermination, in which both the political and intellectual elites of Russia would be eradicated by German forces, in order to ensure a long-lasting German victory. Hitler underlined that executions would not be a matter for military courts, but for the organised action of the military.

The decree, issued by Field Marshal Keitel a few weeks before Operation Barbarossa, exempted punishable offenses committed by enemy civilians (in Russia) from the jurisdiction of military justice. Suspects were to be brought before an officer who would decide if they were to be shot.

The order specified: "The partisans are to be ruthlessly eliminated in battle or during attempts to escape", and all attacks by the civilian population against Wehrmacht soldiers are to be "suppressed by the army on the spot by using extreme measures, till [the] annihilation of the attackers; "Every officer in the German occupation in the East of the future will be entitled to perform execution(s) without trial, without any formalities, on any person suspected of having a hostile attitude towards the Germans", (the same applied to prisoners of war); "If you have not managed to identify and punish the perpetrators of anti-German acts, you are allowed to apply the principle of collective responsibility. 'Collective measures' against residents of the area where the attack occurred can then be applied after approval by the battalion commander or higher level of command"; German soldiers who commit crimes against humanity, the USSR and prisoners of war are to be exempted from criminal responsibility, even if they commit acts punishable according to German law.

Contrary to what was claimed after the war, the Wehrmacht generals such as Heinz Guderian, did not intend to mitigate the records of the jurisdiction of an order, or in any way violate Hitler's intentions. His command was intended solely to prevent individual excesses which could damage discipline within army ranks, without changing the extermination intentions of the order. As part of the policy of harshness towards Slavic "sub-humans" and to prevent any tendency towards seeing the enemy as human, German troops were ordered to go out of their way to mistreat women and children in Russia.

Guidelines for the Conduct of the Troops in Russia