It seems that every time I read about a Nazi who received a life sentence at Nuremburg, the next sentence is something like, "They were released after serving 5 years." Hess is the only high-ranking Nazi that I can think of that spent more than 20 years in prison.
Is there a known reason for why this happened?
Thanks!
The popular memory of the Nuremberg process is both rather simplified and more than somewhat at odds with what actually occurred. Many people often conflate the main tribunal, the International Military Tribunal (IMT) at Nuremberg, with the various national tribunals (NMTs) held by the Allied powers and countries occupied by Germany such as Norway or Poland. The American military government for Germany (OMGUS) did not help matters here though by holding their tribunals in Nuremberg, which is why they are sometimes called the Subsequent Nuremberg Proceedings, but these NMTs were not international affairs like the IMT. The latter tribunal had prosecution and judge teams from all four Allied powers.
So there were a wide variety of tribunals of the surviving Nazi elite. These tribunals though were not the sterling success of popular memory. The IMT got bogged down in procedural issues and the prosecution erred too much on the side of caution and flooded the IMT with evidence. The IMT was part of a wider American-led initiative to educate the German public on the misdeeds of the regime. The IMT and various NMTs by and large failed at this process. Public opinion polls conducted by OMGUS in the American zone showed not only low interest in the tribunals, but a number of German respondents quite openly stated the tribunals were a form of victor's justice. While there were some variations within German opinion, the general gist was that while many Germans did not mind if NSDAP stalwarts like Göring swung, opposition to the process increased when the defendants came from "apolitical" institutions like the military or the bureaucracy. There was some discord among the German public that Jodl and Keitel were in the docket because they were simply officers performing their duty.
This sentiment that the accused were apolitical victims scapegoated by a form of victor's justice only grew over time in Germany. The American NMTs started off strong, but gradually fell victim to many of the problems that befell the IMT. And soon it was not just Germans who were increasingly skeptical of the whole process. There was a marked shift within the American government towards these tribunals away from the mixture of retribution and didacticism of the immediate aftermath of V-E Day. Republican opponents of the Truman administration like Senator Joe McCarthy investigated whether or not the American officials were using torture against German defendants in the Malmedy tribunals. The military chiefs of OMGUS, later renamed HICOG, likewise gave less support to the tribunals. The emerging West German government pushed for clemency for many of those tried between 1946-49 and they managed to tie the clemency issue with West German rearmament. The logic of the Adenauer government was that German soldiers could not in good conscience take up arms against communism if their wartime comrades were languishing behind Allied prisons.
The result of the "Amnesty fever" of the early 1950s was that all but the most guilty of defendants from the Western Allied NMTs were paroled by the mid-1950s. Counter-intuitively, West Germany was arguably the safest place in Europe outside of Spain for former Nazi war criminals to live. So if a defendant managed to avoid a capital sentence in the tribunal period, the odds were very good that they would be released and reintegrated into civil society. Bonn's clemency drive gained a powerful ally in the US which not only bought the logic of clemency to ease German rearmament but many of whose leaders in the 1950s had come around to the position that outside of a few Nazis, the tribunals were counter-productive excesses of the Roosevelt administration. As the leading power in the Western bloc, the US was eased concerns over unrepentant Nazis in corridors of power in the FRG.
The holdouts for this process were the IMT defendants sentenced at Nuremberg like Dönitz. The Soviets had walked away from a wider denazification and tribunal process much like the Western Allies, but recognized that there was political hay to be made by emphasizing how ex-Nazis found their way into power in Bonn. This 1971 cartoon illustrates the type of rhetoric that was common within the Eastern bloc. The SED dictatorship in the GDR would repeatedly highlight the Nazi background of the FRG, as this newsreel on NATO manuevers mentions "Nazi-general Heusinger."
The result of these Cold War games was that the IMT prisoners largely had to serve out their terms in the West Berlin Spandau prison. Bonn and other West German pressure groups pushed for amnesty and earlier releases of many of Spandau's prisoners. But since the release of prisoners had to be governed by four-power consensus (US, UK, France, USSR), the Soviets could veto any early release. There were some conditional releases on the basis of ill-health, but the Soviet hardline meant many of these men served their full term. Both Speer and von Schirach served their full twenty years.
These symbolic games were why Rudolf Hess remained the sole inmate of the massive Spandau prison between 1966 until his suicide in 1987. Hess's imprisonment was fodder for low-grade spy fodder such as the film Wild Geese II, which Patrick Stewart has called the most embarrassing film of his career. Hess himself was a rather marginal figure though in the wartime misdeeds of the Third Reich, so the idea that he held some embarrassing secret that had to be kept under wraps is a bit far fetched. His life sentence was a compromise between the Western Allied judges and the Soviets who wanted Hess to receive a capital sentence because Hess had clear knowledge of Barbarossa and approved of it. Hess's family and advocates in the FRG were a clear liability for either his release or removal to a different jail. Both Hess's wife and his son were knee-deep within the FRG far-right circles and even Hess's advocates in the FRG and Western Allied jailers recognized the noxious politics of these types were a clear liability to eliminate Spandau. The result was that Hess languished in limbo until his apparent suicide in 1987, at which time Spandau prison was destroyed as per Allied agreements.