After the Liberation, he founded the "Corriere Lombardo" newspaper as well as "Costume". Edgardo Sogno was then elected deputy to the Constituent Assembly during the 1946 general election. He contested the June 2, 1946 referendum creating the Republic of Italy, deposing numerous appeals before the "Corte di Cassazione" in the aim of repealing the results of the vote (and restore monarchy). Although this failed, he became diplomat of the new regime, first in Buenos Aires where Juan Peron was head of state, then in Paris, London, Washington DC and, last, he was ambassador in Rangoon. While posted to Budapest, Hungary, in 1956, he helped people flee the country after the Soviet Union invaded Hungary and crushed the Hungarian Revolution.