During the first two years of war, with Romania maintaining a cautious neutrality, Mariu Theodorian became a major proponent of non-alignment, speaking out against supporters of both the Entente and the Central Powers. He had left the National Liberals during the municipal elections of 1914, rallying with the Conservative Party as a disciple of Alexandru Marghiloman and Titu Maiorescu, and therefore of its "Junimea" inner faction. Although not a "Germanophile", Mariu supported a Maiorescu neutralist cabinet, which, he argued, would have been able to gather political support from the Entente, but without going to war; he was also opposed to the Entente because it included the Russian Empire, accused of persecuting the Romanians of Bessarabia. An expert in canon law, he was noted as a critic of the Romanian Orthodox Church, having argued, as early as 1897, that "all true Christians will end up turning to Rome." By May 1908, under guidance from Vladimir Ghika, he had done so himself, being received into the Greek-Catholic community, and working to build a Greek-Catholic church in Bucharest.