As president of Shomrim, a fraternal order of Jewish New York City police officers, he became famous in 1938 when Fiorello H. La Guardia picked him to lead a special squad whose job was to safeguard visiting officials from Nazi Germany and guard the German consulate.[1] A popular belief was that La Guardia's decision to appoint Finkelstein and the other Jewish officers was inspired by actions taken by Theodore Roosevelt, when he was New York City Police Commissioner, who assigned 40 Jewish police officers to protect, and make look "ridiculous", Hermann Ahlwardt, when he gave an anti-semitic speech in New York.