How did the myth of the "innocent Wehrmacht" develop? To what extend, and when, was it rejected both in academic circles and in mainstream culture?

Perhaps the first phenomenon to examine in an effort to answer this question would be the process of "denazification" which occurred in the years immediately following the war. Denazification consisted of removing card-carrying Nazi Party members from positions of power in Germany, although the process also extended in some cases to those who were not official members of the Nazi Party but were clearly involved to a great extent in the operations of the Nazi state during the war. This was an Allied effort, but was carried out differently depending on the Allied power in charge of each zone of Germany. Due to the massive numbers of people who needed to be "denazified," it was determined differently in each zone how the process needed to be handled. In many cases, those who were members of the Nazi party, but were born after a certain year, were exempt. In other cases, it was a matter of the bureaucratic difficulty of managing literally millions of individual case files which led to the abandonment of many cases considered to be less severe by Allied administrators. Timothy Vogt writes in Denazification in Soviet-occupied Germany of the nuances of the process in the Soviet zone, where neither of the prevailing historiographical assessments of "Sovietization" or an effective and rigorous (and successful) denazification fully captures the results of that process. Effectively, Vogt and other historians largely agree that the process was, in all zones, a failure (by its own terms), in that it did not significantly address involvement by German citizens in Nazi programs. Many members of the Wehrmacht were (or should have been) included in the process of denazification.

Where punishments for involvement in German war crimes were more effectively carried out- namely the Nuremberg Trials- members of the Wehrmacht were less conspicuous. Notably, Wilhelm Keitel and Alfred Jodl were tried and executed, but for the most part the trials did not address the crimes of the Wehrmacht. The trials did establish, however, that the "defense of superior order" (or colloquially, "I was just following orders") did not constitute an acceptable defense for war crimes. Nuremberg Principle IV states that "The fact that a person acted pursuant to order of his Government or of a superior does not relieve him from responsibility under international law, provided a moral choice was in fact possible to him."

How much of this translated to either public vilifying or defense of the Wehrmacht, I cannot say.

In academia, the discussion of Wehrmacht "innocence" has been more nuanced. In a now famous essay entitled "One Day in Jozefow: Initiation to Mass Murder," Browning writes of executions of Polish Jews by the Ordnungspolizei or Order Police. He discusses the actions of one particular battalion (Battalion 101), which was responsible for the executions of 1,500 Jews in the town of Jozefow in July 1942. Browning's paper details the offer by the battalion's commander that the men could "pass" on the executions. Due to a variety of factors, the men complied regardless. Browning continued similar research in his book entitled Ordinary Men. In essence, Browning examined the situational factors which led ordinary men to willingly participate in genocide. His determination was that these men did not "set out" to be mass murderers, but rather, due to what were still inexcusable factors of careerism and "peer pressure," ended up becoming just that.

Browning ended up embroiled in a years-long academic debate with another historian, Daniel Jonah Goldhagen, who contended in his book Hitler's Willing Executioners that "ordinary Germans" were so steeped in and indoctrinated by a centuries-old tradition of antisemitism that they eagerly participated in the murder of Jews. This is, in essence, the extent of the debate: Browning's contention that "ordinary Germans" were guilty of war crimes but not eagerly complicit, and Goldhagen's defense of the contrary.

In either case, I would not say that Browning or Goldhagen defended the crimes of Wehrmacht soldiers, or members of groups such as the Order Police, but rather that the argued for varying degrees of willing complicity. Given that this debate was the most widely publicized in the history of Germany's involvement in WWII in quite some time, I would say it encapsulates the general tenor of academia quite well. Neither historian, or those who came out of the woodwork to chime in, would argue for an "innocent" German populace. Other historians have examined the degrees to which ordinary Germans were aware of the Holocaust, but I think I've gone on long enough.