Were there any successful violent or nonviolent protests in Nazi Germany?

Many of the groups involved in protest or resistance (and the two were closely linked, because peaceful, public protests were incredibly dangerous and therefore rare) had no particular end-goal beyond simply demonstrating their opposition to the Nazi state or their non-conformity with state-endorsed norms of behavior. In that sense, some of them were quite successful, but often at a terrible personal cost. We still remember the White Rose and the Edelweißpiraten, which counts as a sort of moral victory for those groups. The Edelweißpiraten might be regarded as doubly successful, having survived the war largely intact.

The case of the organized military resistance is more complex. While some members of the Widerstand intended simply to demonstrate their resistance to Nazism, others had clear political goals for a post-Nazi or post-Hitler Germany. To the extent that they intended their resistance to bring about the fall of Hitler's government, they were obviously failures. The same applies to Hitler's other would-be assassins, like Georg Elser.

Acts or movements of protest that operated on a more limited scale, attempting to ameliorate this or that aspect of Nazi policy or carve out non-Nazi spheres of power or influence within German life, were also generally unsuccessful. The clerical resistance to the T-4 euthanasia program in 1941 (see, e.g., this sermon from Bishop von Galen of Münster), for example, only accomplished stalling the program by publicizing it and then driving it underground. The mentally and physically handicapped were murdered in Germany until May 1945. The Protestant Confessing Church was crushed before the war began. General Johannes Blaskowitz's memoranda of 1940 protesting the early killing operations in Poland changed nothing about the murder of the Jews and intellectuals there.

The so-called "Rosenstraße Demonstration" is a sad exemplar of futile public protest in a fascist regime: As is often the case, the only victory for the protesters was that they were not punished for protesting. In February-March 1943, the arrest of several thousand Jews in Berlin provoked a mass demonstration by their non-Jewish wives and mothers. Protesters feared that the men, who were "exempt" from deportation because they were the husbands, fathers, or children of Aryans, would be deported to the killing centers in the East. Though we can understand the women's reaction, such a deportation was never actually contemplated by the authorities. The men had been arrested in order to have their papers examined and their exemptions confirmed. They were released, only to be scooped up shortly thereafter and sent, per the previous plan, to work camps within the Reich.