Shortly afterward Balbín returned to La Plata and was elected president of La Plata's "Sección Primera" Committee in 1930, the year in which General José Félix Uriburu's coup d'état toppled Yrigoyen. In 1931 the military government called elections, and Balbín was elected congressman for Buenos Aires Province, and Honorio Pueyrredón governor of the province. The UCR victory was not expected by the military government, who instead invalidated the results. Balbín was again elected to Congress in 1940; but he resigned his seat in protest at the fraudulent nature of those elections. In 1945 he participated in the foundation of the "Movimiento de Intransigencia y Renovación" (MIR) together with, among others, Amadeo Sabattini, Arturo Frondizi, Crisólogo Larralde, Oscar Alende, Moisés Lebensohn, and Arturo Illia.