I'm asking specifically about people who were acceptably Aryan and could have easily survived (or even thrived) under the Nazi regime for practical reasons, but couldn't stomach the idea and killed themselves instead.
I have to imagine that there were some educated and liberal-minded German citizens prescient enough to see where things were headed, but unable or unwilling to emigrate or "get with the program."
Do we have any records, particularly suicide notes or final memoirs, of Germans who killed themselves rather than be a part of an evil new regime?
Although the National Socialist regime harped on suicide as a social problem caused by Weimar decadence, suicide rates between the Republic and Third Reich were fairly consistent. The issue is of course complicated by state murders that were claimed as suicide; the KZ camps would periodically claim that inmates who died took their own lives. And Nazi persecutions played a role in pushing suicide rates among certain groups upwards. There were a number of suicides associated with German homosexuals that came as a consequence of renewed state suppression and the suicide rates of German Jews climbed considerably after various Nazi antisemitic actions like the 1933 boycotts or Kristallnacht. Politically-motivated suicides among non-Jews did exist. Toni Pfülf, a Bavarian SPD delegate committed suicide after the rump SPD delegates were part of a unanimous Reichstag vote supporting German equality in disarmament negotiations. There were certainly other Germans upset over the direction their country's politics had taken and the looming war added further anxieties. Yet a Pfülf-style exit was not a common one for German liberals in the Third Reich. German liberals tended to ride out the Third Reich and, counter-intuitively, they seldom felt the screws of state power.
In Germany, "liberalism" was very much an ideology of the German Mittelstand and held a great deal of influence among the educated, largely Protestant, German middle classes. German liberalism actually had a leg up in the nineteenth-century political evolution of Germany, despite setbacks like the abortive Paulskirche parliament in the revolutions of 1848. Nineteenth-century German liberals often had the organizational experience, a roughly coherent ideology, and a corpus of public intellectuals who could assume parliamentary positions in the newly formed German Reichstag. The main liberal party, the National Liberal Party (NLP), was initially the largest party in the first elections in 1871, and it was joined by the German Progress Party, which was a more left-leaning liberal party. However, German liberalism was ill-prepared for the age of mass politics at the turn of the century, and liberal parties found shrinking electoral returns when faced with competitors like the SPD and Catholic Centre who appealed to much broader segments of the population. Additionally, German liberalism often fractured into various smaller parties under the pressures of mass politics. The advent of war arrested some of these centrifugal trends and German liberals were among the most vocal proponents of Germany's war aims and the Burgfrieden, an idea of a national community undivided by political affiliations.
It was in this context of splintering and shrinking political power that German liberalism entered into the Weimar Republic. Even though German liberals had played a considerable role in drafting the constitution, they were a minority political opinion. By this point the NLP had dissolved as the main liberal party, and instead the German Democratic Party (DDP) and German People's Party (DVP) were the main liberal parties during Weimar. Although individuals from German liberal circles managed to assume prominent leadership positions within the Republic's coalitions, the electoral strength of liberalism was as a whole waning throughout the Republic.
This wider trend of weakening political power defined much of German liberals' responses to the rise of Hitler, which ranged from disgust and rejection to co-option of the ideals of the NSDAP. Liberals within the more left-wing orientated DDP tended to place themselves in opposition to Hitler between 1929-33, but it is important to realize that German liberals were often not opposing Hitler per se, but rather a wider turn in German politics towards extremism both on the left and far-right. Yet German liberals were not above the wider radicalization process that transformed Weimar politics in the 1930s. Many of the DDP and DVP intellectuals embraced various völkisch ideas developed during the war, and often saw the rise of communism as a greater threat to Germany than Hitler's NSDAP. This ideological overlap with some of the tenets of National Socialism made it much more difficult for liberals to form political coalitions with either the SPD or Centre parties in opposition to Hitler and the various conservative political parties seeking to end the Republic.
The result was that the picture of liberals in Germany was either of a doomed rearguard against the rise of Hitler or a cowardly surrender to the Nazis. But liberals' responses to various Nazi political initiatives was often quite complex, and elides simple notions of last stands or surrender. The position of various liberals in the passage of Enabling Act in 1933 was emblematic of this multifacted response to the rise of the dictatorship. With one lone exception, all of the DStP (a successor of sorts to the DDP) delegates in the Reichstag voted for the Enabling Act, a seemingly about-face to liberal democratic principles. But the rationale for supporting the Enabling Act varied among the deputies. Some of the support was due to a deepening cynicism about the Republic and its institutions, and some liberals like Ernst Lemmer joined the NSDAP outright. Other liberals, especially those influenced by Friedrich Naumann's thinking, disliked the crudeness of the NSDAP's politics and leaders, but saw some virtue in its economic and social policies. Hjalmar Schacht was the most prominent liberal in this category, seeing in dictatorial powers the key to restructuring the economy. Still other liberals saw the Enabling Act as the least-worst alternative between an Unrechtsstaat (lawless state) and a restricted Rechtsstaat (state defined by laws). By sanctioning the Act, the state was still acknowledging the importance of German law and jurisprudence instead of proceeding without the sanction of law. Finally, other liberals saw their affirmative vote as a tactical move that preserved their continued opposition to Hitler. A number of liberal recognized that the Act had enough support to pass, but also that Hitler was not above using extralegal means if thwarted. Therefore, it was important not to give Hitler a pretext to further clamp down on liberal politicians and intellectual circles. As the liberal leader Hermann Dietrich explained in a letter to a colleague angered by the vote:
after it was certain that all the bourgeois parties would vote for the Enabling Act, it became difficult for our representatives to do otherwise if they did not want to stand in opposition with the SPD. That would have had the same consequence that we would have been placed in the same camp as the Marxists, and it would have made it easier for government to take measures against us. It was also necessary, moreover, to take into consideration democratic officials, who have a difficult enough struggle already. Here again we had to support measures we privately opposed. This can no longer be avoided under the present circumstances.
In hindsight, this type of accommodation politics proved to be quite disastrous and only entrenched the dictatorship. Schacht, for example, was sidelined in the Economics ministry after his opposition to rearmament found little support in the Chancellery and far from reining in the NSDAP's reliance upon extralegal methods, the Enabling Act only encouraged these methods. Yet, for many German liberals, accommodation worked as a political stratagem pf sorts. Outside of more stalwart political opponents like Thomas Mann, the Third Reich was willing to let liberal circles alone if they kept their opposition relatively quiet. Dietrich, for example, retired to the legal profession, kept his Jewish secretary and refused to participate in the NSDAP legal associations. Liberal publications, like Theodor Heuss's Die Hilfe had relatively little state interference and censorship so long as they did not broach political topics openly. The relatively light hand of the Nazi state on German liberalism encouraged what later was termed "inner emigration" in which Germans retreated away from politics into their own professional milieus and social circles. Both contemporaries and subsequent generations have critiqued inner emigration as a cowardly disengagement (and with a great deal of justification), but from the view of those within these liberal circles, such disengagement was a form of resistance to a state that aspired to a totalitarian control of society. By keeping these aspects of German life, whether intellectual, legal, or in the churches, relatively free from NSDAP influence, they were preparing the ground for a post-Hitler Germany that would keep these traditional spheres alive within the German body politic.
Suicide is of course a difficult topic for historians of the Third Reich as it is often incredibly difficult to disentangle issues of personal mental health and the wider socio-political context of the German dictatorship. The Nazi state certainly did pursue policies that encouraged some Germans to take their own lives. The violation of the Volksgemeinschaft was not only a legal matter for individual Germans, but one that encouraged social alienation and shunning on top of legal matters. But suicide was not an especially common method of coping for self-identified German liberals. The dictatorship generally did not suppress German liberals if they watched their mouths in public and their dislike for the regime did not cross into treason. The latter transgression was naturally rather plastic in the eyes of Nazi justice and some prominent liberals like Heuss did operate in Germany with a sword of Damocles over their heads. Inner emigration though was a much more prevalent method among German liberals to cope with the Third Reich than a politically-motivated suicide.