On May 25 1967, Mossad Director Meir Amit met the CIA station chief in Tel Aviv, John Hadden. Many years later, the late Gen. Amit gave us the startling transcript. Despite Amit’s warning that a major Soviet move into the Middle East was in the offing, the American was adamant: Israel must not pre-empt a Soviet-instigated and armed Egyptian onslaught. Hadden then added a threat: “If you attack, the United States will land forces on Egypt’s side, in order to defend it.”

Recently declassified US documents confirmed that such an American contingency plan was dusted off in mid-May 1967. But no forces had been allocated, nor operational orders issued, by the time Israel did strike first on June 5. So no GI Joes found themselves fighting against Israeli soldiers, alongside the Soviet landing forces that were poised aboard some 30 ships of the USSR’s Mediterranean Eskadra, or the Soviet paratroops who spent the war on the runways of forward airbases.

Needless to say, Moscow would never have contemplated defending Israel, had the Arabs struck first, which the Soviets urged them not to do, but rather to provoke an Israeli first strike that would legitimize USSR support for the victims of aggression. This planned Soviet intervention was obviated only by the unexpectedly devastating effect of Israel’s opening air strike and the resulting rout of Arab ground forces, not by any US counteraction. Indeed, when Egypt falsely accused the United States (and Britain) of taking part in the air offensive, the US Sixth Fleet was ordered away from the combat zone, and Washington declared itself “neutral in thought and deed.”

Discovering the abortive Soviet intervention in Russian veterans’ memoirs illustrated the risk historians take if they project the superpower alignment of later periods onto pre-’67 years. It was a lot more asymmetric then; Israel’s triumph in the Six-Day War did push the Americans farther into a corner, but by default after Egypt broke off relations. The USSR did the same toward Israel.

The USSR’s response to its setback in June 1967 was, by contrast, proactive, decisive and aggressive. The Moscow leadership quickly determined that in order to retain its Middle Eastern influence, reassure its anxious clients elsewhere, and redeem the reputation of Soviet weaponry, it had to help the Arabs prepare for a rematch.

Within hours of the ceasefire on the Suez Canal front, a massive sea- and airlift replenished Egypt’s losses of materiel. Soviet marines and air-defence crews took up positions opposite Israel until Egyptian forces could regroup, a combat presence of Soviet regulars that would be expanded to a full SAM division and fighter-jet regiments during the ensuing War of Attrition in 1969-1970. The toll they took on Israel compelled them to accept a disadvantageous ceasefire. This created the preconditions for Egypt’s cross-canal offensive on Yom Kippur in 1973.

The blueprint for this operation, the list of requisite weapons, and the training plan for Egyptian forces were drawn up by a top-level contingent of Soviet military advisers as early as summer 1967. The payback for Moscow was to turn Egyptian ports and airfields into de facto Soviet bases, fulfilling a centuries-old Russian aspiration to project power into the Mediterranean (do you see an analogy with Syrian bases today? We do, too).

Where were the Americans? Both the administrations of Lyndon Johnson and Richard Nixon subordinated the Middle East to their prime objective — extrication from Vietnam. Henry Kissinger considered that in favour of this and other benefits of his Détente policy, he could manipulate the Soviets to restrain their Arab clients. He cut secret deals with Moscow at Israel’s expense. But the Soviets blindsided him and the Yom Kippur surprise was only the worst instance.

The United States did finally come through with its own emergency airlift, but only after Israel suffered a lasting national trauma with over 2,200 fatalities. Egypt ultimately switched to the American camp as it needed America for the peace as much as the USSR for the war. Arguably, it was the demands of brokering this deal, rather than the previous competition with Moscow, that raised and fixed the level of American political, military and economic commitment to Israel and Egypt alike.

Isabella Ginor and Gideon Remez are associate fellows of the Truman Institute, Hebrew University of Jerusalem. The Soviet-Israeli War 1967-1973 is published by Hurst

Read all our Six-Day War coverage here