Fiorello LaGuardia: Nu, Vus Titzuch, Paisan?

In 1922, the Democratic Tammany Hall political machine ran a Jewish candidate against Fiorello LaGuardia, and distributed flyers claiming that LaGuardia was anti-Semitic. LaGuardia, who had a Jewish mother and his Italian father's last name, responded by challenging his opponent to a debate in Yiddish. He spoke Yiddish fluently and his opponent did not.

Source: "Fiorello LaGuardia," Jewish Virtual Library.