The Six-Day War that erupted in 1967 may have created a new Middle East, but the broader Arab-Israeli conflict to which the war belonged was anything but new. It had begun decades earlier, driven by the ongoing refusal by Israel’s neighbors to accept Jewish sovereignty in the Middle East. As Jordan’s King Hussein admitted before the United Nations General Assembly shortly after the war, "Today’s war is not a new war but part of the old war," which he said would continue until Arab demands were met (Associated Press, Lighting Out of Israel, 156).
The combatants in 1967 — Israel, Egypt, Jordan and Syria, as well as Iraq and other Arab states — were for the most part the same as those who fought in the first Arab-Israeli war of 1948, in which Israel fought off an invasion by Arab countries. Rhetoric in the days leading up to the Six-Day War also echoed that from 1948. For example, on May 15, 1948, the day Arab states launched their attack on Israel, Arab League Secretary General Azzam Pasha announced that "[t]his will be a war of extermination and a momentous massacre which will be spoken of like the Mongolian massacres and the Crusades." Almost exactly nineteen years later, on May 18, 1967, Egypt’s government-controlled Voice of the Arabs radio station mimicked this language, announcing that "the sole method we shall apply against Israel is total war, which will result in the extermination of Zionist existence." Two days later, Syrian Defense Minister Hafez Assad declared: "I, as a military man, believe that the time has come to enter into a battle of annihilation."
The general animosities that led to the Six-Day War began even before 1948. Arab opposition to the Balfour Declaration and Jewish nationalism in British Mandate Palestine had fomented conflict as early as the 1920s, when Palestinian Arab rioters, often instigated by Palestinian religious leader Haj Amin al Husseini, attacked Jewish communities in Tel Chai, Jaffa, Jerusalem and elsewhere. Particularly bloody were the attacks on August 1929, when rioters massacred over 100 Jews across British-controlled Palestine, mainly in the ancient city of Hebron. These deadly riots continued sporadically throughout the 1930s, leading Jewish armed groups to engage in defensive — and eventually pre-emptive and retaliatory — battles with Arab fighters and villagers.
Another of the central factors that pushed the region to war — the status of international waterways leading to Israel — also had its roots in the decades before 1967. In the late 1940s and early 1950s, Egypt blockaded the Suez Canal and the Straits of Tiran to shipping destined for Israel. These restrictions not only harmed the nascent Jewish state, but were considered a violation of the 1949 armistice resolution signed by Egypt and Israel, the Constantinople Convention of 1888, Security Council Resolution 95, and, in the words of historian Howard Sachar, "international legal precedents for gulfs and bays flanked by the territories of more than one littoral state" (A History of Israel, 456). It wasn’t until 1956 — after Israel, France and the United Kingdom invaded and then quickly withdrew from Egypt’s Sinai peninsula — that passage through the Straits of Tiran (but not the Suez Canal) was opened to Israeli shipping. The presence of a United Nations Emergency Force stationed in the Sinai between 1956 and 1967 helped deter Egypt from reimposing its blockade.
By the summer of 1967, however, the UN troops would be gone, old threats and blockades would reappear, and the drift to war would reach its climax.
Yet, though the antagonism of earlier fighting remained firmly in the background, war was hardly expected or pre-planned. Before 1964 there was, in the words of Mideast scholar Nadav Safran, "eight years of nearly perfect quiescence of the Arab-Israeli conflict" — despite the unwavering Arab position that Israel must be destroyed (Israel: The Embattled Ally, 386). Even after 1964, when attacks against Israel by the Palestinian Fatah organization and skirmishes along the Israeli-Syrian border occurred with increasing regularity, neither Israel nor its neighbors (excepting maybe Syria) were itching to rush to war.
But this all changed in May 1967, when war seemed almost certain. The deterioration was rooted in several factors, not the least of which was geopolitics of the Cold War. As American relations with Egypt soured, the Soviet Union stepped up its influence in the Arab world, working to build (pro-Soviet) Arab unity by focusing Arab attention on their common enemy, Israel. The prospect of fighting against America had a deterrent effect on Egyptian President Gamal Nasser, just as fear of the Soviet Union weighed on Israeli Prime Minister Levi Eshkol.
But as the weight of the Soviets shifted more firmly behind the Arabs' anti-Israel positions, an emboldened Nasser moved to reclaim Egypt's position as leader of the Arab world — a position that had eroded in part because of the Nasser's stance that the Arabs should hold off on outright confrontation with Israel until the Arab world could successfully marshal its collective resources against the Jewish state. Any show of military strength against Israel, then, would help the Egyptian president regain his lost stature. The atmosphere in the spring of 1967 convinced Nasser that the time was ripe to flex his muscles.