Another development centered on Cyprus. In 1963 Makarios's demand for reduction in the powers of the Turkish minority caused fighting to break out on the island, and all-out war loomed when Turkey threatened an invasion to defend Cypriot Turks. Only the forceful intervention of the United States president, Lyndon B. Johnson, prevented an invasion in early 1964. The United Nations peacekeeping forces that entered Cyprus to prevent war at that point have remained on the island since that time. The Cyprus conflict convinced many in the military of the need to step up war readiness.

The third event was the succession of the inexperienced twentyfour -year-old Constantine II to the throne upon the death of his father Paul in March 1964. Just one month before, the Center Union had won a resounding victory, garnering 52.7 percent of the popular vote and a majority 173 seats in parliament to push the right out of power. Thus the military was deprived of both its royal patron and its connection with the majority party. In the eyes of the right, such changes meant that public order was deteriorating at the same time that war with Turkey seemed imminent.