I feel like this question has probably been asked before, but I cannot find it and perhaps my googling skills need work. Anyway, my question is in the title.
What was their party membership and essentially how prominent was this movement? Was their a notable amount of people sympathetic to the nazis in the years leading up to the war? After the war?
To borrow from an earlier post I wrote on this subject:
he main support in the US for the Nazi party came from the German-American Bund, led by its own little wannabe Furher, Fritz Kuhn, a German born, naturalized citizen, but with some strings pulled by the German Foreign Office itself. With roots in several earlier organizations, "Friends of the Hitler Movement" and "Friends of the New Germany", it was founded in 1936, and agitated, mainly within the German-American community, for pan-German unity behind the Nazi regime. It never succeeded in gaining much penetration into the 30,000,000 person community, peaking at 8,500 members, although about 20,000 people attended their infamous rally at Madison Square Garden on Feb. 20, 1939. The organization would falter soon after when Kuhn was indicted for embezzling party funds - in large part due to the dogged perseverance of Mayor Fiorello LaGuardia and DA Thomas E. Dewey. He beat some of the charges, but not all, and was sentenced to several years in Sing Sing. Now under the leadership of G. Wilhelm Kunze, the Bund never got back on a solid footing, and when it was officially disbanded on Dec. 9th, 1941, there was barely any organization to be rid of.
Sources
Bell, Leland V. "The Failure of Nazism in America: The German American Bund, 1936-1941." Political Science Quarterly 85, no. 4 (1970): 585.
Evans, Richard J.. New York, US: The Coming of the Third Reich. Penguin Books, 2005. General history, part of a trilogy. Best general history of Nazi Germany out there, IMO
Fischer, Klaus P.. Hitler and America. Philadelphia, US: University of Pennsylvania Press, 2011. Heavily covers US-American relations in the period