Historians generally attribute Israel's costly victory to two Israeli lapses, a successful enemy deception operation and a very astute Egyptian war plan. The lapses and enemy deception scheme still shape Israeli security policy, especially toward Iran and its nuclear weapons program.
Israel's first lapse occurred when its intelligence services failed to detect the size and scale of enemy military preparations. Spies noticed more tanks on Syria's side of the Golan Heights and increased activity on Egypt's side of the Suez Canal. However, they failed to discern the Syrian and Egyptian strategic intent.
Short hours before Egyptian forces crossed the Suez Canal on October 6, Israel's second lapse occurred when its national command authority failed to act with decisive force. Though the spies now confirmed a major enemy buildup, the government decided to wait and forgo a pre-emptive attack.
Egypt's and Syria's military and political deception operation deceived Israeli spies and leaders. Both nations skillfully camouflaged their war preparations.
Egypt's Sinai plan utilized clever combat-engineer techniques and leveraged Israeli battlefield elan. Egyptian engineers would use high-pressure water hoses to breach the Canal's sand walls. A massive artillery preparation would suppress Israeli defenders in their Bar Lev Line fortifications while assault divisions crossed. Once in Sinai, Egyptian forces would remain beneath an air defense "umbrella" provided by sophisticated Soviet-made surface-to-air missiles (SAMs) and anti-aircraft guns. The "umbrella" would ambush over-confident Israeli pilots. (Syria would employ a similar "umbrella" over the Golan.) Meanwhile, Egyptian ground forces would ambush Israeli tanks, counter-attacking hell-for-leather. Egyptian infantry armed with rocket-propelled grenade launchers and anti-tank missiles would hide until the tanks drew close. When possible, the infantrymen were told to wait until they could hit the Israeli tanks from the flank or rear. Egyptian president, Anwar Sadat, believed that even a limited defeat of Israel's vaunted armored forces would have galvanizing morale effects in Egypt and throughout the Arab world.
On October 6, Egyptian forces breached the canal in two hours and pushed beyond Israel's thin Bar Lev Line forts. On the Golan Heights, three Syrian armored divisions attacked two Israeli brigades. The Golan brigades took horrendous casualties, but never broke. Their stand may have won the war, but for the next 96 hours the victory and defeat hung in dreadful balance as Israeli reservists raced to the front.
The air defense umbrellas over the Canal and the Golan took a terrible toll on Israeli aircraft. Israel acknowledged the loss of 102 aircraft, over half lost in the first three days of combat.
Though Israel had lost some 500 tanks (400 in Sinai), by October 10 both Arab offensives had stalled. Israel counter-attacked in Sinai and on October 15 crossed the Canal into Africa.
U.S. Secretary of State Henry Kissinger pressed both sides for a ceasefire, to begin October 22. Israeli tanks approached Damascus, and Syria agreed to the ceasefire. In Sinai and Africa, fighting persisted. As Israeli forces cut off an Egyptian army in Sinai, on October 24 the Soviet Union threatened to send Russian soldiers to Egypt to enforce the ceasefire. The U.S. responded by putting its forces on alert, including its nuclear forces. The war officially ended October 25, though ceasefire violations continued.
The disengagement talks between Egypt and Israel on October 28 were rancorous, but in retrospect laid the groundwork for what became the Camp David Peace Process.
The superpower posturing and nuclear-saber rattling was dangerous, but understood to be diplomatic signals. Avner Cohen, however, contends that on October 9 the situation became so dire that Israel considered using nuclear weapons. Israel didn't, but its desperate national leaders peered into the nuclear abyss.
The October War demonstrated to many Israelis that a decision to pre-emptively strike, deferred by even a day or two, could put Israel's existence at risk. An intelligence failure in a confrontation with a nuclear-armed Iran could be fatal. Israelis compare the shock of the October 1973 surprise attack to the American reaction to Pearl Harbor. Iran's ayatollahs should take note.