Quinn, who experienced discrimination growing up in Los Angeles, participated in various civil-rights and social causes. He provided funding for Latino advocacy group the Spanish-Speaking People’s Congress. He assisted in fundraising efforts for the legal defense of Mexican-American youth in the racially charged Sleepy Lagoon murder trial in 1942.[citation needed] While in Paris, several other prominent Americans and he composed a petition endorsing the 1963 March on Washington; the petition, which was reprinted in several high-profile publications, was intended to rally support among Americans living abroad, according to Elliott Miller, writing in CounterPunch.