Together with the vast majority of the electorate, the Liberals boycotted the vote, depriving the newly elected government of all valid popular support. Through the rest of 1915 and 1916, relations between the Liberal and monarchist factions continued to deteriorate as the two sides adopted more rigid and radical positions. Popular opinion vacillated. For example, when French and British troops landed in Macedonia in December 1915 despite the protests of the king, most Greeks supported Constantine's position that the maneuver by the Entente Western Allies violated Greek sovereignty. But when monarchist military leaders allowed eastern Macedonia to fall to the Central Powers in May 1916, public opinion was outraged. Greek national opinion was becoming increasingly unclear.

By mid-1916 Greece stood on the brink of civil war. In Thessaloniki a clandestine pro-Venizelos military organization, the Ethniki Amina (National Defense), launched a coup against the government, with support from the British and French. In October Venizelos returned from Crete to lead the provisional government in Thessaloniki and form a new army to support the Entente. By the end of 1916, the British and French had recognized the provisional government and had blockaded most of Greece to force concessions from Constantine, who feared that Venizelos would topple him. For 106 days, no goods were imported or exported at central and southern Greek ports. Near-famine conditions developed in some areas. Under the leadership of Ioannis Metaxas, former aide-de-camp of Constantine and future dictator of Greece, a reactionary paramilitary unit, the League of Reservists, was founded. The league undertook a systematic campaign of terror and violence against Venizelists in Athens and against anyone who did not support the monarchy. Once a pattern of violent, sectarian reprisals had begun, it would prove very hard to stop.