Hungary–Romania relations
During World War II, Hungary and Romania became allies and participated in the war against the Soviet Union. But after the coup on 23 August 1944 Romania switched sides and fought against Hungary. Consequently, Soviet and Romanian troops invaded Hungary, occupied Northern Transylvania by October 1944 and re-established the Romanian administration in the region in March 1945. The 1947 Treaty of Paris reaffirmed the borders between Romania and Hungary as originally defined in Treaty of Trianon 27 years earlier, thus confirming the return of Northern Transylvania to Romania.
National Liberal Party-Brătianu
After the outbreak of World War II, Romania was, despite its neutrality, a target for the hostility of both Germany and the Soviet Union after the Molotov–Ribbentrop Pact ("se Romania during World War II"). Gheorghe I. Brătianu attempted to determine more Axis sympathy towards Greater Romania's borders by discussing the matter with the German Foreign Minister Joachim von Ribbentrop—consequently, he was placed under surveillance by Siguranţa Statului, on Carol's direct orders. In 1940, Greater Romania was disestablished through the Soviet annexation of Bessarabia and Northern Bukovina, the cession of Northern Transylvania to Hungary, and that of Southern Dobruja to Bulgaria. Although being, as himself later pointed out, "a Germanophile", Gheorghe I. Brătianu signed his name to a protest regarding the German-enforced Arbitration, and later stated that he had "preferred Germany's hostility to its scorn".