National Security Advisor Henry Kissinger and Hanoi's Le Duc Tho resume peace negotiations in Paris.
After the South Vietnamese had blunted the massive North Vietnamese invasion launched in the spring of 1972, Kissinger and the North Vietnamese had finally made some progress on reaching a negotiated end to the war. However, a recalcitrant South Vietnamese President Nguyen Van Thieu had inserted several demands into to the negotiations that caused the North Vietnamese negotiators to walk out of the talks on December 13.
President Richard Nixon issued an ultimatum to Hanoi to send its representatives back to the conference table within 72 hours "or else." The North Vietnamese rejected Nixon's demand and the president ordered Operation Linebacker II, a full-scale air campaign against the Hanoi area. On December 28, after 11 days of round-the-clock bombing (with the exception of a 36-hour break for Christmas), North Vietnamese officials agreed to return to the peace negotiations in Paris.
When the negotiators returned on January 8, the peace talks moved along quickly. On January 23, 1973, the United States, North Vietnam, the Republic of Vietnam, and the Viet Cong signed a cease-fire agreement that took effect five days later.