From what I could gather, current scholarship is a bit divided on the "Nazi sympathies" issue when it comes to Schumpeter. He was indeed investigated by the FBI in 1939 as part of a sort of standard practice when it came to emigrants from Nazi Germany who wanted to become US citizens (also because his wife apparently was a scholar of Japanese economics) but could not find anything apparent.

And while Schumpeter certainly assisted former colleagues in getting out of Nazi Germany, in one of the most recent biographies, John Medearis' Jospeh Schumpeter, 2009, the introduction goes into detail on some of Schumpeter's diary entries and anti-Semitic comments that most likely form the basis for his suspected Nazi sympathies.

According to Medearis, Schumpeter had a serious of prejudices against Jews, which he would went in private. He insisted that his help for colleagues was out of a duty to personal acquaintances and not as a protest to Nazi racial policies (this was the early 30s) and according to a biography written by his student Robert Loring Allen (1991) wrote in his diary that "We must either have either Hitler or else the Jews." and "I am as antisemitic as [Carl] Schmitt or some kind of rich German-American."

Medearis, who also highlights that Schumpeter's anti-Semitism never made it into his public writing and that he never advanced an anti-Semitic argument in said writing, from this constructs an argument that while Schumpeter's anti-Semitism is obvious from these and other incidents, that he did not share in what Saul Friedländer called the redemptive anti-Semitism of the Nazis, meaning the idea of a metahistorical struggle between Jews and Aryans and so forth. Rather, he asserts that Schumpeter shared in the anti-Semitism and especially the anti-Bolshevism that was so widely spread in conservative, bourgeois circles in the Weimar Republic. Meaning that he certainly regarded Jews in a negative light, especially those who refused to assimilate and that he might have been a supporter of such measure such as limiting the number of Jews eligible to study at university as well as other discriminatory measure but that he did not share the eliminationist element of Nazi anti-Semitism.

An important factor here in my opinion is that Schumpeter was politically socialized in fin-de-siecle Vienna, also known as the Vienna of Karl Lueger. Studying in the capital of the monarchy in the early 20th century and gaining his PhD in 1906, Schumpeter experienced Vienna under the rule of the famous and infamous Karl Lueger. Lueger, a founder of the Christian Social Party in Austria, is not only known for modernizing the city of Vienna in the late 19th and early 20th century but also for being one of the most effective politicans who weaponized anti-Semitism as part of Austrian politics.

Lueger, though not a pan-Germanist, employed anti-Semitics rhetoric in his elections campaigns, sponsored bills to reduce or prohibit the emigration of Jews from Romania and Russia to Vienna, frequently referred to Budapest as "Judapest" (a pun on Jews and plague) and took, despite being from the Christian Social end of the political spectrum, such an atni-Semitic position that at first, the Emperor did prevent him from becoming major. During his later reign, he attempted to prevent Jews from learning and doing certain professions, and was also one of the popularizes of the "Jewish socialist" stereotype. Not for nothing did even Hitler claim Lueger to be one of his most important influences in developing his anti-Semitism.

Schumpeter, as the son of German-speaking Catholic parents who moved to Vienna from Moravia and who attended in the Theresianum one of Vienna's most prominent Catholic schools, would most likely find himself not very much at odds with Lueger. While he might have disagreed Christian Social politics at times, their generally conservative and anti-socialist position he most likely viewed positively. It was this party after all that invited him to become a state secretary in the newly created Ministry of Finance of the Republic of Austrian in 1919. And while he soon conflicted with both the Christian Socials and the Socialists, it is easy to surmise where his political leanings lay in the early days of Austria.

In this sense, I would advance the hypothesis that Schumpeter's anti-Semitism needs to be understood in the context of Lueger Vienna as a politically socializing force. This would make him part of the segment of German and Austrian bourgeois class that was so crucial in paving the way for Nazi anti-Semitism and take-over, both on an ideological and political level, even if it didn't automatically make them Nazis.

His writing such as "We must either have either Hitler or else the Jews." and his self-comparison to Carl Schmitt is a further indication of that. These intellectuals saw in Hitler a necessary way to save Germany from Jewish communism and while Schumpeter wasn't around because he left earlier than that, Schmitt thought in a way he could intellectually overtake Nazism and mold it in light of his ideas (something that didn't work that well).

In this sense, Schumpeter was like so many German and Austrian conservatives (here used in the sense of Austrian politics at the time) and anti-communists in that they regarded the Nazis as too brutish, too prole for themselves and their sophisticated intellectualism as well as shared their anti-Semitism as long as it was in line with their fin-de-siecle version of it. As Lueger once said "I determine who is a Jew", talking about how his politics discriminated against poor, orthodox Jews from the East rather than against some of the assimilated Jews in Vienna. From the scattered evidence we have, this seems to have been Schumpeter's position also, helping Jewish colleagues escape while at the same time seeing Hitler as a maybe unwelcome but necessary alternative to "the Jews" in the early 30s.

In this sense, Nazi sympathies on a level of personal politics is certainly not completely unfounded though he did not politically agitate in their sense in the US, hence why the FBI cleared him for naturalization. His anti-Semitism was certainly reprehensible. Viewed in the context of his time, it was also not uncommon and as a general phenomenon we know recognize it as paving the way for Nazism. At the same time, he was not a Fritz Julius Kuhn of the German-American Bund and while Nazism was viewed as generally horrible by many of his colleagues, his fin-de-siecle anti-Semitism would have certainly found sympathies among US academia and politics.