In the post Second World War Eastern Europe the Vatican attempted to protect its believers aware that the ideological and political climate was changing with the advent of the Soviet age. Forced by the Romanian regime that made Nuncio Andreea Cassulo a persona non grata in 1946 the Vatican nominated as replacement in February 1946 the American Bishop of Savannah, Gerald Patrick O’Hara. The bishop arrived in Romania only in January 1947, the authorities reticent to offer permission for him to take over the Nunciature offices in Bucharest. He will reside in Romania for three years witness to the installation of the communist administration in Bucharest and the devastation of the Catholic Church in Romania. He was never acknowledged by the Romanian authorities as nuncio and remained papal regent, an envoy to Romania. During his stay the Romanian authorities suspended the Concordat with the Vatican, arrested with one exception the entire Roman Catholic hierarchy and forced the unification between the Greek Catholic Church and the Romanian Orthodox Church, imprisoning its hierarchy and relegating the Greek Catholics refusing the union to the religious underground. Not solely a witness, during Bishop O’Hara’s stay in Romania he managed to put together the Catholic underground, legitimizing several hierarchical tiers and the financing of the clandestine clergy and communities. He maintained the continuity of the canonical jurisdiction until he was forced out of Romania by the communist authorities on July 1950 accused of spying for the West in a sweep operation of the Romanian secret police. Bishop O’Hara’s case study will illustrate the type of local politics that the Holy See had at the installation of the communist regimes in East Central Europe.