The Yom Kippur War triggered a U.S. nuclear alert in 1973

The Yom Kippur War began on October 6, 1973, when Egypt and Syria launched coordinated surprise attacks on Israeli forces in the Sinai Peninsula and the Golan Heights on the holiest day of the Jewish year. Before it ended, it brought the United States closer to nuclear confrontation with the Soviet Union than at any point since the Cuban missile crisis.

Washington was caught out too. Despite warnings from Jordan’s King Hussein and Soviet leader Leonid Brezhnev, Richard Nixon and Henry Kissinger believed the military balance made an Arab attack unlikely. Israel suffered heavy losses in the first days; by October 9, after a failed counter-attack against Egypt, it asked for American arms. U.S. planes began landing on October 14, and two days later Israeli units crossed the Suez Canal.

The night of DEFCON III

Many accounts say the war ended with UN Resolution 338 on October 22. It did not. The ceasefire broke down amid Israeli violations, the Security Council passed a second resolution the next day, and on October 24 Brezhnev sent Nixon a letter proposing joint U.S. and Soviet troop contingents in Egypt — warning that otherwise Moscow might have to consider “taking appropriate steps unilaterally.”

At 11:41 p.m., Joint Chiefs chairman Admiral Thomas Moorer ordered U.S. commands to DEFCON III, the highest state of peacetime alert for nuclear-armed units; the 82nd Airborne was alerted and carriers moved toward the eastern Mediterranean. The reply rejecting Brezhnev’s proposal went out under Nixon’s name, though the president, absorbed by Watergate, did not see it at the time. The crisis eased on October 25, when Resolution 340 called for a ceasefire and a pullback to the October 22 lines.

The war’s costs ran long. The U.S. airlift prompted Arab oil producers to embargo shipments to the United States and parts of Western Europe. In Israel, anger at the intelligence failure led to the Agranat Commission and, in 1974, the resignations of Golda Meir and Moshe Dayan — and, eventually, to the 1979 Egypt–Israel peace treaty.