After serving as an advisor for Archduke Franz Ferdinand, counseling on the latter's projects to redefine the Habsburg states along the lines of a United States of Greater Austria, Maniu moved towards the option of a union with the Romanian Old Kingdom when the Archduke was assassinated in Sarajevo in 1914.
The National Peasants' leaders, Iuliu Maniu and Ion Mihalache, were tried on trumped-up charges of plotting to overthrow the government (the so-called Tămădău Affair) and were both sentenced to life imprisonment.